p15.04.01 d10 final report part 2 v1.1

Evolution of the Surveillance Infrastructure

Document information

Project title Surveillance Infrastructure Rationalisation

Project N° 15.04.01.

Project Manager THALES

Deliverable Name

Evolution of the Surveillance Infrastructure

Deliverable ID D10-02

Edition 00.01.00

Template version 02.00.01

Task contributors

DFS, EUROCONTROL, THALES

Please complete the advanced properties of the document

Abstract

This paper forms part 2 of the final deliverable of the WP15.04.01 project.

This report summarises the drivers for change that are foreseen to influence the European surveillance infrastructure and proposes a roadmap of how the changes will influence the evolution of the infrastructure. The roadmap can be used as a contributor when considering means for rationalisation of an ANSPs surveillance infrastructure or when assessing the surveillance specific aspects of higher-level strategic documents such as the ‘European ATM Master Plan’ and the ‘Strategic Guidance in Support of the Execution of the ATM Master Plan’ and for compiling an ANSPs local surveillance plans.

Project ID15.04.01. D10-02 - Evolution of the Surveillance Infrastructure Edition: 00.01.00

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Authoring & Approval Prepared By

Name & company Position / Title Date

Andrew Desmond-Kennedy / EUROCONTROL Project Member 19/10/2012

Reviewed By


Philippe Juge / THALES Project Manager 29/10/2012

Daniel Muller / THALES Project Member 29/10/2012

Thomas Oster / EUROCONTROL Project Member 29/10/2012

Christos Rekkas / EUROCONTROL Project Member 29/10/2012

Michel Borely / EUROCONTROL Project Member 29/10/2012

Marcel Sobottka / DFS Project Member 29/10/2012

Roland Mallwitz / DFS Project Member 29/10/2012

Andreas Herber / DFS Project Member 29/10/2012

Approved By


Philippe Juge / THALES Project Manager 29/10/2012

Andrew Desmond Kennedy / EUROCONTROL Project Member 29/10/2012

Marcel Sobottka / DFS Project Member 29/10/2012

Document History Edition Date Status Author Justification

00.01.00 19/10/2012 New Document

IPR (foreground) This deliverable consists of SJU foreground.

©SESAR JOINT UNDERTAKING, 2012. Created by [Member(s)] for the SESAR Joint Undertaking within the frame of the SESAR Programme co-financed by the EU and EUROCONTROL. The opinions expressed herein reflects the author’s view only. The SESAR Joint Undertaking is not liable for the use of any of the information included herein. Reprint with approval of publisher and with reference to source code only.

SESAR Joint Undertaking Point of Contact

For further details regarding the SESAR Programme please visit www.sesarju.eu or for specific information regarding the WP15.04.01 please contact: [email protected] (Please ensure that the subject field of the mail contains the message: Query Regarding WP15.04.01)


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Table of Contents EXECUTIVE SUMMARY .................................................................................................................................... 6

1 INTRODUCTION.......................................................................................................................................... 7

1.1 PURPOSE OF THIS PROJECT .................................................................................................................. 7 1.2 PURPOSE AND SCOPE OF THIS DELIVERABLE ....................................................................................... 7 1.3 INTENDED READERSHIP .......................................................................................................................... 7 1.4 INPUTS FROM OTHER PROJECTS ............................................................................................................ 8 1.5 ACRONYMS AND TERMINOLOGY............................................................................................................. 8

2 INFLUENCES ON THE EVOLUTION OF EUROPEAN SURVEILLANC E ........................................ 9

2.1 OPERATIONAL ENVIRONMENT AND DRIVERS FOR CHANGE .................................................................. 9 2.1.1 General .......................................................................................................................................... 9 2.1.2 Operational Environment .......................................................................................................... 10 2.1.3 RF Environment ......................................................................................................................... 10 2.1.4 ATC Controller Efficiencies....................................................................................................... 11 2.1.5 Composition of the Aircraft Fleet ............................................................................................. 12 2.1.6 Legislation ................................................................................................................................... 16

2.2 AVIONICS SUPPORTING SURVEILLANCE .............................................................................................. 19 2.2.1 Equipage Requirements............................................................................................................ 19

2.3 DEVELOPMENT STATUS OF SURVEILLANCE TECHNIQUES................................................................... 22 2.3.1 General ........................................................................................................................................ 22 2.3.2 Independent Cooperative Surveillance Techniques ............................................................. 22 2.3.3 Dependent Cooperative Surveillance Techniques ................................................................ 23 2.3.4 Independent Non-Cooperative Surveillance .......................................................................... 26 2.3.5 Ground Data Fusion .................................................................................................................. 28

2.4 DEPLOYMENT STATUS OF THE SURVEILLANCE INFRASTRUCTURE ..................................................... 29 2.4.1 The Current European Surveillance Infrastructure ............................................................... 29

3 ROADMAP TO THE SURVEILLANCE INFRASTRUCTURE OF 2030 ............................................ 35

3.1 TARGET STATE DESCRIPTION............................................................................................................... 36 3.1.1 Principal Differences between the Current and Future Scenarios for Surveillance ......... 36

3.2 PHASE 1 OF THE ROADMAP - TODAY TO 2020 .................................................................................... 41 3.2.1 Description of the Phase 1 Surveillance Infrastructure ........................................................ 42 3.2.2 Surveillance Coverage .............................................................................................................. 44

3.3 PHASE 2 OF THE ROADMAP - 2020 TO 2030 ....................................................................................... 44 3.3.1 Description of the Phase 2 Surveillance Infrastructure ........................................................ 45 3.3.2 Surveillance Coverage .............................................................................................................. 46

3.4 ROADMAP IN GRAPHICAL FORM........................................................................................................... 47 3.4.1 Airborne surveillance by ground .............................................................................................. 47 3.4.2 Aircraft-Aircraft Surveillance ..................................................................................................... 48

4 SUMMARY OF TASKS IDENTIFIED AS NECESSARY TO SUPPORT THE TRANSITION TO THE TARGET STATE ...................................................................................................................................... 49

4.1 IDENTIFIED WORK AREAS..................................................................................................................... 49 4.1.1 Support the Development of ADS-B In Applications............................................................. 49 4.1.2 Support the Provision of Additional ADDs from an Aircraft: ................................................ 49 4.1.3 1030/1090 Spectrum Activities................................................................................................. 49 4.1.4 Investigate and Develop Means to Provide Oceanic or Remote Region Surveillance .... 50 4.1.5 Enable ADS-B Equipage on ALL Aircraft ............................................................................... 51 4.1.6 Maintain the Surveillance Infrastructure ................................................................................. 51 4.1.7 Support the Development of MSPSR Products and Associated Standards ..................... 52

5 CHANGES TO THE SESAR MASTERPLAN AND THE SUPPORTING GUIDANCE DOCUMENT. ...................................................................................................................................................... 53

5.1 SESAR ATM MASTERPLAN ................................................................................................................ 53 5.2 SUBJECTS FOR INCLUSION IN THE SESAR ATM MASTERPLAN ......................................................... 55 5.3 STRATEGIC GUIDANCE IN SUPPORT OF THE EUROPEAN ATM MASTER PLAN................................... 55


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6 CONCLUSIONS ......................................................................................................................................... 57

7 REFERENCED DOCUMENTS ................................................................................................................ 58

APPENDIX A ACRONYMS AND TERMINOLOGY ............................................................................... 60

APPENDIX B DEFINITIONS ..................................................................................................................... 64

B.1 SURVEILLANCE TERMS ......................................................................................................................... 64 B.2 MISCELLANEOUS TERMS ...................................................................................................................... 67


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List of tables Table 1: Key Dates Contained in Published European Commission Implementing Regulations.........19 Table 2: Summary of Independent Cooperative Surveillance Technique Availability ..........................23 Table 3: Summary of Dependent Cooperative Surveillance Technique Availability.............................25 Table 4: Summary of Independent Non-Cooperative Surveillance Technique Availability ..................28 Table 5: Secondary surveillance radars (Mode A/C) installations ........................................................31 Table 6: Secondary surveillance radar (Mode S) installations..............................................................32 Table 7: Operational Improvements Placing Requirements Upon Surveillance...................................54 Table 8: Categories of air traffic surveillance sensors ..........................................................................66

List of figures Figure 1: Long Term Trend in European IFR Air Traffic (Source: Eurocontrol)....................................13 Figure 2: Predicted traffic in 2030 .........................................................................................................13 Figure 3: Airborne surveillance by ground ............................................................................................47 Figure 4: Aircraft to Aircraft Surveillance ..............................................................................................48 Figure 5: Aeronautical surveillance system ..........................................................................................65

List of Standalone Appendices The information presented in the two tables that form the following appendices is too condensed to be viewed in A4. Consequently they are provided in a standalone form.

Appendix C: Correlation between Operational Improvements, Enablers and ADS-B Functionality

Appendix D: Correlation between Operational Improvements, Enablers and Further Surveillance Developments to Support the Future ATM Infrastructure


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Executive summary This report describes drivers for change and how the surveillance infrastructure is foreseen to evolve over the next 20 years.

The objective of the surveillance infrastructure is to provide the required surveillance functionality and performance to enable a safe, efficient and cost-effective Air Traffic Management service. The current surveillance infrastructure is mainly composed of mono-pulse and sliding window (Mode A/C) Secondary Surveillance Radar (SSR), SSR Mode-S and Primary Surveillance Radars (PSRs). Recently, however, technological developments such as Automatic Dependent Surveillance–Broadcast (ADS-B) and Wide-Area Multilateration (WAM) have reached maturity and are being deployed across Europe. Emerging technologies such as Multi-Static PSR (MSPSR) and Hybrid Surveillance (ACAS using ADS-B message content) have demonstrated their feasibility and once developed, validated and deployed can influence the future surveillance infrastructure. In parallel, new performance targets and associated operational requirements are emerging from Single European Sky and SESAR initiatives. These factors will drive changes to the existing surveillance infrastructure. This evolution needs to be managed, for it will also be influenced by an extensive range of other factors such as global interoperability, civil-military coordination, the introduction of functional airspace blocks (FABs), and changes to the composition of the aircraft fleet with the introduction of very light jets and unmanned aircraft. Furthermore, cost and radio frequency spectrum efficiency considerations will lead to a rationalisation of the current infrastructure, in which legacy systems will be phased out as soon as practicable and new, more efficient technologies will be introduced. Surveillance systems are a key enabler of the SESAR future operational concept. They are expected to be “leaner” and more efficient in the future – achieving safety and service continuity objectives by combining a layer of ADS-B with a layer of secondary surveillance (provided either by SSR Mode S or WAM). Primary radar coverage will also be available, where required (e.g. for safety or security reasons), either by classic (mono-static) PSR or possibly in the form of multi-static PSR (MSPSR). In addition to ground-based surveillance, ADS-B will also enable the development of new airborne surveillance operational services including air traffic situational awareness, spacing, separation and self-separation. Subject to design, validation and the establishment of a positive business case it is also possible that an aircrafts ADS-B transmissions could be relayed to the ground via satellite. This could, if considered necessary, provide improved surveillance in Oceanic and Remote areas. To achieve these changes, the avionics carried on board an aircraft must become a fully integrated element of the surveillance infrastructure. The scope of surveillance systems will extend to embrace an increasingly diverse range of avionic components – such as GNSS, traffic computers and cockpit display systems, as well as the transponders. The activities conducted in recent years have established a solid foundation which allows the European surveillance infrastructure to meet future needs and upon which SESAR can build.


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1 Introduction

1.1 Purpose of this Project In recognition that the future surveillance infrastructure is to be leaner and more efficient in respect of a number of key performance indicators a key objective of the project was to detail a methodology that promotes a rationalisation and adaptation to the Surveillance Infrastructure. (See Ref Doc 1)

A secondary objective of this project was to develop a roadmap, this document, to support a transition to the future Surveillance Infrastructure – as envisaged in the ATM Masterplan (Ref Doc 2). The roadmap or strategy is to exploit the benefits that new and emerging surveillance techniques can bring whilst taking due cognisance of its context within the evolution of the wider Civil/Military ATM Infrastructure.

1.2 Purpose and Scope of this Deliverable The purpose of this document is to provide a general, high-level description of the current European surveillance infrastructure, the status of surveillance techniques and guidance concerning the anticipated evolution and their capability to meet the demands of a changing operational environment. It proposes a roadmap detailing a path to achieving the surveillance infrastructure required to meet future needs in an efficient manner taking advantage of new Surveillance techniques and technologies such as ADS-B, WAM and MSPSR. It describes how the changes foreseen may impact upon the SESAR ATM Masterplan (Ref Doc 2) and to supporting literature such as the document ‘Strategic Guidance in Support of the Execution of the European ATM Masterplan’ (Ref Doc 3). The surveillance roadmap indicates when the surveillance techniques will be available and how the different techniques will be used in support of existing operational services and future improvements developed by SESAR. It also provides an indication of the drivers for change behind the evolution. The scope of this Roadmap does not cover weather radar, wake vortex detection, airport surveillance or debris detection. Its primary focus is upon the ground based surveillance of the airspace and the supporting avionics used in TMA and En-Route applications and surveillance used to support air-air applications. The impact of ACAS upon the 1030/1090 MHz frequencies is addressed within the scope of this paper. The roadmap identifies the need for supporting legislation and a support infrastructure but does not address operational procedures or system components such as controller tools.

1.3 Intended readership The stakeholder groups considered throughout the scope of this project were:

• Aeronautics industry.

• Airport operators.

• Airspace users.

• Air Navigation Service Providers.

• EUROCONTROL Agency.

• International organisations.

• Regulatory bodies.

• Military Authorities in their different roles as regulator, ANSP, airspace user and airport operator.

• Non-ECAC Organisations.

• European Commission.

• SESAR Joint Undertaking.


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1.4 Inputs from other projects In addition to the information derived from the numerous supporting activities conducted within the scope of SESAR WP15.04.01 further influences also arose from:

• SESAR WP 15.04.05a Surveillance Ground System enhancements for ADS-B

• SESAR WP 15.01.06 Spectrum Management and impact assessment

• SESAR WP 9.47 re Hybrid Surveillance (ACAS and ADS-B)

• SESAR Masterplan Update Cycle and

• B4.3 project activities.

1.5 Acronyms and Terminology A comprehensive list of acronyms and definitions is provided in Appendix A.


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2 Influences on the Evolution of European Surveilla nce This section synthesises the key findings of the previous activities conducted within the scope of the SESAR WP15.04.01 project and how these could influence the evolutionary path of the European surveillance infrastructure.

The focus of the WP15.04.01 Project is upon TMA and En-Route applications however much of the content may be equally applicable to other surveillance applications.

2.1 Operational Environment and Drivers for Change

2.1.1 General The objective of a surveillance infrastructure, be it civil, military or combined, is to provide the required functionality and performance to enable a safe, efficient and cost-effective service. New performance targets and associated operational requirements are emerging from Single European Sky legislative packages and SESAR initiatives. Whilst not explicit in introducing requirements upon ‘surveillance’ they introduce implicit requirements and drive changes to the existing surveillance infrastructure. This evolution needs to be managed, for it will also be influenced by an extensive range of other factors such as global interoperability, civil-military coordination and changes to the composition of the aircraft fleet with the introduction of very light jets and unmanned aircraft. Through the increasing deployment of Wind-Turbines, the clutter environment is changing. Furthermore, cost and radio frequency spectrum efficiency considerations will be conducive to a rationalisation of the current infrastructure, in which legacy systems will be phased out as soon as practicable and new, more efficient technologies will be introduced. The number of stakeholders with responsibilities within the sphere of surveillance is increasing. Current stakeholders include civil and military air navigation service providers, aircraft operators (civil and military, commercial and general aviation), avionic manufacturers, regulatory authorities (civil and military national authorities and the European Aviation Safety Agency (EASA)), EUROCONTROL and the European Commission. Each of these brings unique contributions which reflect their specific expertise and perspective. The traditional means of surveillance (Independent Non-Cooperative – PSR and Dependent Cooperative -SSR) remain dominant in supporting current European ATM operations. SSR Mode S is in increasing operational use throughout Core Europe. WAM is being increasingly deployed – initially addressing niche requirements but its use and market penetration is now expanding. Whilst certain applications in the use of ADS-B 1090 MHz are currently under validation pending wider availability of appropriately configured avionics to enable full operational use it is noted that initial exploitation of ATSAW and ADS-B NRA within Europe has commenced. The ASTERIX data-format is the main format used for the transfer and sharing of surveillance information. Changes arising through the introduction of functional airspace blocks (FABs) are influencing the surveillance architecture required. These have the potential to reduce the requirements for surveillance sensors providing cross-border surveillance and afford a means to support the wide-spread sharing of surveillance data. Such aspects can be key contributors to realising efficiency gains. It is recognised that a degree of overlap of surveillance cover is required to support the transfer of radar control (see ICAO EUR Doc 7030 § 6.2.5 Ref Doc 8) and to ensure appropriate service continuity. An assessment of the benefits that data sharing (including ‘releasable’ military data) can bring could potentially reduce this level of duplicated coverage. This would bring benefits in terms of reduced cost but also reduced transponder occupancy and reduced 1030/1090 MHz spectrum occupancy.


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2.1.2 Operational Environment

2.1.2.1 Performance Requirements An ANSP needs to demonstrate to their Regulatory Authority that the performance that is required by and achieved by their surveillance infrastructure is acceptable and appropriate however the recent emergence of new technologies such as WAM and ADS-B has necessitated a change to the way performance requirements for surveillance systems are documented. The EUROCONTROL Specification for ATM Surveillance System Performance which details the required performance of a surveillance infrastructure in a technological independent manner (Ref Doc 9) could be used as one of the means to support ANSPs in this regard. The performance of the surveillance system relies upon aircraft being appropriately equipped with correctly functioning and interoperable transponders and appropriate avionics.

2.1.3 RF Environment There is increasing pressure for ATM to improve the manner in which the RF spectrum currently assigned to it is managed and used. This is coming not only from parties external to ATM but the increasing use of the 1030/1090 MHz band is also increasing pressure from within.

Congestion of the RF environment is already becoming a problem area in dense traffic and ground system areas and, unless appropriate mitigations including rationalisation are introduced, it will continue to get worse and could eventually compromise system performance.

The RF spectrum is core to the correct functioning of all surveillance techniques and technologies. Demands upon the spectrum need to be managed and improvements need to be made to accommodate the increasing demands being placed upon it – both from within ATM and from external sources.

2.1.3.1 Spectrum Overview Until 2030 ATC surveillance in Europe will rely on 3 families of surveillance technology

1. Independent Cooperative Surveillance (using 1030/1090 MHz) (Such as SSR, SSR Mode S and WAM)

2. Dependent Cooperative Surveillance (using 1090 MHz)

3. Independent Non Cooperative Surveillance (using spectrum allocated within L Band and S Band).

In addition the 1030/1090 MHz SSR bands also support the safe operation of airborne safety nets (i.e. ACAS) and of forthcoming air to air applications (e.g. in-trail procedure) and are needed to support the deployment of cooperative surface surveillance systems at airports.

ADS-B operations rely on GNSS and the RF bands in which it operates (dependent upon which GNSS technology is used on board the aircraft. Options could include GPS, GLONASS, Galileo or COMPASS-Beidou).

Either Active or Passive Multi-static PSR technology could, subject to development and deployment, replace classical mono-static PSR technology. As Active MSPSR is expected to utilise an L-band frequency bandwidth narrower than those currently assigned to classical PSR it could be envisaged that some portions of both the L-Band and the S-Band could be released for non-ATM application. Widespread deployment of MSPSR may require a co-ordinated frequency allocation mechanism to fully exploit the ability to reduce spectrum requirements.

As reflected in SESAR WP15.1.6 SESAR Spectrum Strategy (Ref Doc 10) it is assumed that the spectrum currently allocated to these types of systems will continue to be used up to at least 2030 and must be protected against interferences from other systems to ensure the safe operation of surveillance ATC.


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A mix of different links to support ADS-B operations is possible. However such an approach introduces a degree of system complexity by requiring multiple band receivers or by requiring additional ground function to rebroadcast the data received from one link onto the other link (ADS-B Rebroadcast) and in some instances uses elements of spectrum that are already heavily utilised. Whilst these links may be used elsewhere on the globe this roadmap for Europe does not foresee the use of links other than 1090 MHz for Surveillance applications.

2.1.3.2 1030/1090 MHz Frequency Band The high number of SSR Mode A/C radars configured with relatively high interrogation rates and interrogator power has, over recent years, lead to congested usage of the 1030/1090 MHz frequency band.

As ACAS and all the cooperative surveillance techniques are dependent upon this frequency band its use is considered to be fundamental to the future of surveillance. Deploying an alternative band would be expensive, time consuming and would introduce technical difficulties. It is preferable to manage, monitor and protect the current frequency assignments in recognition that the 1030/1090MHz as a valuable asset that is to be used with care. The protection of the 1030/1090 MHz frequencies is a key objective of this surveillance roadmap.

Various measures ranging from the removal of spectrally inefficient Mode A/C SSRs (such as promoted through the Implementing Regulation No 1206/2011 Ref Doc 6) through to improvements in ACAS technologies (hybrid surveillance) or the clustering of SSR Mode S ground-stations will lead to improvements in this band and obviate the need for deployment of an alternative frequency band. The deployment of WAM techniques has the potential to reduce excessive transmissions in the 1030/1090 MHz band when compared with conventional SSR systems. However it should be noted that Active Wide Area Multilateration systems configured with broad-beam or omni-directional transmit stations can also place a significant impact upon this frequency band and the surveillance sensors that depend upon it.

2.1.3.3 Primary Surveillance Frequency Bands There is growing pressure being exerted by non-ATM users, particularly mobile phone and television bodies, for access to the two frequency bands (L Band and S Band) used by civil and military PSR radars and that are allocated internationally for radio-navigation purposes.

It is reported that some governments are considering the introduction of spectrum charging. As ‘traditional’ Primary Surveillance Radars require a broad RF spectrum their continued use may become expensive for some ANSPs. See WP15.1.6 D26 (Ref Doc11) for further details.

Such demands upon spectrum usage are placing pressure upon the use of conventional Primary Surveillance Radars. Recent technological developments point to a new type of Independent Non-Cooperative surveillance technique, Multi-Static PSR, which could, subject to verification of viability, address these issues.

2.1.4 ATC Controller Efficiencies Surveillance systems support Air Traffic Controllers in conducting their tasks in an efficient manner.

Modern systems, such as Mode S EHS, ADS-B and WAM, not only present a clearer, less garbled image but also provide additional benefits over conventional systems by providing timely indication that an aircraft is not complying with, or deviating from ATCs instructions. The fact that the information is constantly being updated without the need for ATC intervention or voice communications between ATC and the aircrew can also help alleviate RF congestion in the frequencies used for voice communications. The attribution of such benefits to surveillance is difficult to quantify.

Modern and emerging surveillance systems provide improved mitigation against human error and also provide benefits in terms of human factors such as:

• Safety

• Workload and capacity

• Efficiency


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Modern Surveillance Systems (and the tools they support) provide benefits in terms of safety through:

• Clear presentation of call-sign and level

• Automatic same level indication

• Improved situational awareness

o Use of certain down-linked aircraft parameters (DAPs) and 25’ altitude reporting to improve radar tracking algorithms.

o Conflict detection tools using values derived from Mode-S DAP or ADS-B ADDs are potentially more consistent than those using data derived from radar plots.

• Potential reduction in level busts

o Display of Vertical Stack Lists

o Down-linking of pilot Selected Flight Level supports the resolution of issues stemming from:

� Correct pilot read-back followed by incorrect action

� Incorrect pilot read-back by correct aircraft

� Pilot read-back by incorrect aircraft

o Same Selected Flight Level Alert

Similarly benefits can be accrued in terms of workload, capacity and efficiency:

• Reduction in Radio Transmission (between controller and pilot).

• Display of DAPs.

• Overall enhanced situational awareness.

• Reduced clutter.

• Garbling, compared to conventional SSR Mode A/C, is reduced through clustered Mode S, ADS-B and WAM.

• Improve management of aircraft in stacks.

ANSPs may wish to consider how best to exploit these potential benefits when conducting an upgrade or a rationalisation exercise (see Ref Doc 1) that introduces new surveillance techniques which make additional aircraft derived data available and whether their introduction merits consideration within the scoring mechanism applied within the rationalisation methodology.

2.1.5 Composition of the Aircraft Fleet

2.1.5.1 Changes to the Aircraft Type and Numbers Despite recent declines in the numbers of flights made per year the long term trend is predicted to remain in an upward direction albeit less that the capacity requirements predicted within the original high level SES objectives.

The EUROCONTROL Long-Term Forecast of IFR Flight Movements 2010 to 2030 report (Ref Doc 12) focuses on the developments between 2016 and 2030.

The forecast is for 16.9 million civil IFR flight movements in the EUROCONTROL Statistical Reference Area (ESRA) in 2030, 1.8 times the traffic in 2009. This is an average growth of 1.6%-3.9% per year (with 2.8% considered most likely). The growth will be distributed unevenly in time and across regions. It will be faster in early years, stronger in Eastern Europe and for arrivals/departures to/from outside Europe than for intra-Europe flights. It should be noted that neither military IFR and OAT traffic nor General Aviation is included in these predictions yet may impact upon the requirements of the surveillance systems.


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Figure 1: Long Term Trend in European IFR Air Traff ic (Source: Eurocontrol)

Growth, in percentage terms is expected to be stronger in Eastern Europe where the market is relatively less mature and the States are catching up with the more developed Western economies. The total number of flights is represented in Figure 2.

Future air traffic will be limited by capacity at the airports, 0.7-5.0 million flights will not be accommodated in 2030, 5%-19% of the demand. Congested airports create pressure on the flow of operations in the network and will exacerbate delays. Resolving such issues may introduce requirements for additional surveillance sensors.

Even with airport capacity restrictions airports will grow. In 2030, it is predicted that there will be 13-34 airports as big as the top 7 are now. Some of the faster growing East-European airports will join the top 25. European hubs will be faced with competition from hubs outside Europe, primarily in the Middle-East.

Figure 2: Predicted traffic in 2030


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2.1.5.2 Aircraft fleet types The composition of the catalogue of aircraft types operating in European airspace is evolving. The introduction of super heavy jets, such as the A380 will bring challenges to areas such as airport design and operation as well as wake vortex issues however, from a surveillance perspective the fact that the aircraft is fully equipped to operate in controlled airspace means that it does not need further significant consideration. (It is to be noted that sufficient provision is included in ADS-B specifications to accommodate a broadcast of distance between the transponder location and nose tip – necessary for surface movement operations).

The potential consequences of changes to fleet type through the introduction of Very Light Jets (VLJs), Remotely Piloted Aircraft (RPAs) and low Radar Cross Section (RCS) composite body aircraft should also be considered from a surveillance perspective.

2.1.5.2.1 Very Light Jets (VLJs)

Very Light Jet (VLJ) is the term used to describe a range of small jet aircraft, seating 4-8 people, with a maximum take-off weight below 3000 kg. They do not have a separate ICAO classification and are considered as Light Aircraft.

They have very dissimilar performance characteristics to commercial jet aircraft with lower landing and cruising speeds – differences that may place new requirements upon the surveillance infrastructure.

Whether or not VLJs are to be ACAS equipped remains under discussion. As such aircraft operate in the same airspace as commercial aircraft there are arguments for amending the current ACAS thresholds to accommodate such aircraft. However should a large number of VLJs become operational or the revised ACAS thresholds include a large number of aircraft that are currently excluded from these requirements there will need to be a consideration of the impact upon the 1030/1090 MHz frequency.

Development and deployment of VLJs is under way with forecasts of a significant enough growth in Europe for there to be concern as to their likely impact, and how they will be integrated with today’s larger commercial traffic.

2.1.5.2.2 Remotely Piloted Aircraft (RPA)

2.1.5.2.2.1 RPA Operations

The number of RPA in operation across the globe is steadily increasing. Within Europe, besides military applications, a number of RPA are already being used for civilian applications such as high voltage power cable ‘health-assessments’, and crop and fishery tasks as well as border control and to support policing.

It is anticipated that the number of platforms in operation will increase further with their regular operation in European airspace foreseen from 2018. ICAO and EUROCAE specifications for such aircraft are currently being developed.

The basic principle being adopted for the operation of RPA operated in controlled airspace (outside of visual line of sight of the ground-based ‘pilot’) is that the aircraft must adhere with the same avionic equipage required for conventional aircraft e.g. they need to carry transponders if the airspace requires them for conventional aircraft. (The deployment of ACAS on such aircraft is not yet decided).

The application of this principle simplifies matters from a surveillance perspective however a significant amount of effort may still be required by ANSP’s and their regulatory counterpart to consider how operations of such platforms are to be integrated into daily practice and how aspects like the allocation and management of the 24 bit ICAO aircraft code are to be managed and the manner in which ATC are made aware of indicators such as ‘loss of control link’. As such aircraft may only exhibit a low radar cross section the ANSP may also need to consider whether the existing PSR are capable of providing a safety mitigation in the event it is required if the aircrafts transponder fails (see section 2.1.5.2.3).

SESAR Work-packages 9 and 15 address to a limited extent the integration of RPA into the European ATM infrastructure. There are elements of RPA operations that are particularly well suited to SESAR given that its wide scope embracing all of ATM includes SWIM (System Wide Information


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Management), improved sense and avoid, advanced communications, precise trajectory management, ASAS (Airborne Separation Assistance Systems) and autonomous flight. The following section focuses upon the potential changes that may be required to surveillance functionality to support operations by such aircraft.

2.1.5.2.2.2 Possible Impact of Remotely Piloted Air craft upon Surveillance The widespread deployment of Remotely Piloted Aircraft (RPA) into operations in controlled airspace is expected to happen towards the latter end of the time-period of the ATM Masterplan. There are three matters, namely 'sense and avoid', equipage requirements and flight profiles that may have implications upon surveillance components in terms of performance requirements, design and integration into operations.

• A "Sense and Avoid' function will be required in the RPA not only to avoid all obstructions in the flight path; buildings, terrain, pylons, wires but also other aircraft. However RPA platforms cover a broad spectrum of size, weight and performance envelopes. Smaller RPA may not be capable of carrying or powering the conventional ACAS systems. Some larger RPA platforms may not be able to follow ACAS Resolution Advisories. Consequently new systems, procedures and practices will need to be developed.

• RPAs may have a reduced radar cross section - this could mean that coverage provided by current PSRs, including military, may be reduced for such aircraft. A reduction in detection capability would impact upon the system safety case.

• The flight profile or performance envelope of some RPA may also impact upon the performance requirements of the surveillance infrastructure. Some RPA will fly above the altitude of normal manned aircraft and will impact upon current separation minima only during ascent and descent phases of flight. Other large RPA will operate 'non-conventional' missions flying at slow speed, not necessarily conducting 'point to point' operations. Similarly some RPA may fly at lower altitudes in airspace not currently covered by existing surveillance systems. The performance envelop of an RPA (Tighter turns, higher altitude, slower / almost static operations at height) may place new demands upon mono and multi-sensor trackers and controller support tools.

• ATC may introduce a specific user requirement regarding confirmation of whether an aircraft is manned or unmanned. Such information could be broadcast from RPA equipped with ADS-B or Mode S EHS capabilities. The receipt, processing and data transfer for presentation of such data will place new requirements upon the surveillance infrastructure. Consideration could also include whether an indication to a controller is necessary that a RPA has lost contact with its ‘pilot’ and is therefore not under control but is following a pre-defined return route.

These aspects will need to be addressed to ensure that RPA can be operated safely in controlled and non-controlled airspace. (See SESAR Work-packages 9 and 15)

2.1.5.2.3 Reduced Radar Cross Section

Recent developments in composite technologies have provided aircraft manufacturers with a material that is both light and strong and thus ideal for aircraft construction. Such material however can also exhibit a low radar cross section (RCS). Informal feedback from ANSP’s has confirmed that poor PSR returns are being observed from some small ‘pleasure type’ aircraft built from composite materials.

The presence of low RCS or micro-light aircraft operating in the vicinity of, and in recorded cases infringing upon controlled airspace are influencing ANSP’s decisions regarding the retention and required performance of independent non-cooperative surveillance systems.

When conducting assessments of system performance requirements and capabilities ANSP’s should consider whether current PSR will continue to provide adequate safety mitigation in the event they are to be used when the cooperative surveillance system or avionics fails or to detect airspace infringement of non-avionic equipped aircraft. The detection of small aircraft with an RCS that is lower than for today’s fleet of aircraft could place increasing demands upon non-cooperative surveillance systems.

Whilst the requirement to provide safety mitigation for aircraft with a low RCS could, potentially, be achieved through the use of military Air Defence radar data it may be more likely to form a user requirement for the development or procurement of new PSRs (with improved detection capabilities)


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or in the development of MSPSR as this technique is likely, subject to successful development and validation, to fulfil this requirement.

2.1.6 Legislation

2.1.6.1 Summary The European Commission now adopt an active role in supplementing the legislative capabilities of individual states National Supervisory Authorities or Civil Aviation Authorities. The publication of AICs, AIPs or other local legal instruments can now be supplemented by regulations published by the European Commission.

A number of important developments have recently taken place with regard to ATM. These include the publication of a number of European Commission Regulations. These supplement existing legislation and include:

• Commission Implementing Regulation (EU) No 677/2011 laying down detailed rules for the implementation of Air Traffic Management (ATM) network functions and amending Regulation (EU) No 691/2010. (Published 7th July 2011) (Informally known as the NM IR) (Ref Doc 4)

• Commission Implementing Regulation (EU) No 1207/2011 laying down requirements for the performance and the interoperability of surveillance for the single European sky. (Published 22nd November 2011) (Informally known as the SPI IR) (Ref Doc 5)

• Commission Implementing Regulation (EU) No 1206/2011 laying down requirements on aircraft identification for surveillance for the single European sky. (Published 22nd November 2011) (Informally known as the ACID IR) (Ref Doc 6)

• Commission Regulation (EU) No 1332/2011 laying down common airspace usage requirements and operating procedures for airborne collision avoidance. (Published 16th December 2011) (Informally known as the ACAS IR) (Ref Doc 7)

The publication of Implementation Regulation No 1207/2011 (Ref Doc 5) by the European Commission establishes a European wide instrument to introduce ADS-B carriage requirements upon aircraft whose take off mass or maximum cruising true airspeed exceed defined thresholds. These requirements are one of the greatest influences behind how the surveillance infrastructure will change in the next decades.

To gain the maximum benefit from an ADS-B surveillance infrastructure it is necessary that 100% of the aircraft under ATC control are appropriately ADS-B equipped. Achieving this will require additional mandates. In the first instance it is anticipated that these will be published locally to introduce ADS-B requirements upon all aircraft within defined volumes of airspace and to preclude ADS-B transmissions by non-approved ADS-B configurations. Introducing such requirements in designated airspace could also be achieved through additional European wide legislation such as a subsequent Implementing Rule.

Furthermore the Implementing Regulation No 1207/2011 not only supplement the existing mandates published for core Europe for such aspects as Mode S ELS and EHS but it also replicates such requirements across all of Europe.


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2.1.6.2 Key Dates in Legislation Affecting the Surv eillance Infrastructure The legislation identified above introduces a number of milestone dates which pave the way to the surveillance infrastructure of 2030. In summary form those that become effective after the publication date of this paper are detailed in ‘Table 1: Key Dates Contained in Published European Commission Implementing Regulations’ below:

Date Milestone Source of Requirement

8 Jan. 2015 Aircraft with an individual certificate of airworthiness first issued on or after 8 January 2015 that are operating IFR/GAT flights in European airspace are to be equipped with secondary surveillance radar transponders that have appropriate Mode S ELS capabilities.

Implementing Regulation for performance and interoperability of surveillance for the single European sky.

8 Jan. 2015 Aircraft with a maximum certified take-off mass exceeding 5 700 kg or having a maximum cruising true airspeed capability greater than 250 knots and with an individual certificate of airworthiness first issued on or after 8 January 2015 that are operating IFR/GAT flights in European airspace are to be equipped with secondary surveillance radar transponders and avionics that have appropriate Mode S EHS and ADS-B capabilities.

(Aircraft of specific types with a first certificate of airworthiness issued before 8 January 2015 that have a maximum take off mass exceeding 5 700 kg or a maximum cruising true airspeed greater than 250 knots that do not have available on a digital bus on-board the aircraft the complete set of parameters required for Mode S EHS compliance may be exempted from complying with the EHS requirements).


5 Feb. 2015 By 5 February 2015 Member States shall ensure that a secondary surveillance radar transponder on board any aircraft flying over a Member State is not subject to excessive interrogations that are transmitted by ground-based surveillance interrogators and which either elicit replies or whilst not eliciting a reply are of sufficient power to exceed the minimum threshold level of the receiver of the secondary surveillance radar transponder.

Member States shall also ensure that the use of a ground based transmitter operated in a Member State does not produce harmful interference on other surveillance systems.


5 Feb. 2015 Member States shall ensure that, by 5 February 2015 at the latest, a safety assessment is conducted by the parties concerned for all existing surveillance systems.



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1 Dec. 2015 All aircraft required to equip and operate ACAS shall be configured with ACAS II v7.1

Implementing Regulation on common airspace usage requirements and operating procedures for airborne collision avoidance.

1 July 2017 Aircraft of specific types with a first certificate of airworthiness issued before 1 January 1990 that have a maximum take off mass exceeding 5 700 kg or a maximum cruising true airspeed greater than 250 knots may be exempted from complying with the requirements of SSR antenna diversity.

The Member States concerned shall communicate to the Commission by 1 July 2017 at the latest, detailed information justifying the need for granting exemptions to these specific aircraft types based on the criteria of paragraph 5.


7 Dec. 2017 Civilian Aircraft Operators shall ensure that:

(a) aircraft with an individual certificate of airworthiness first issued before 8 January 2015, are equipped with secondary surveillance radar transponders with appropriate ELS capabilities

(b) aircraft with a maximum certified take-off mass exceeding 5 700 kg or having a maximum cruising true airspeed capability greater than 250 knots, with an individual certificate of airworthiness first issued before 8 January 2015 are equipped with appropriate Mode S ELS and ADS-B avionic configurations.

(c) fixed wing aircraft with a maximum certified take-off mass exceeding 5 700 kg or having a maximum cruising true airspeed capability greater than 250 knots with an individual certificate of airworthiness first issued before 8 January 2015 are equipped with appropriate Mode S ELS and EHS avionic configurations.


7 Dec. 2017

1 Jan. 2019

1 July 2016

1 July 2018

Member States shall ensure that, by 7 December 2017 State aircraft operating IFR/GAT flights in European airspace are equipped with secondary surveillance radar transponders with appropriate ELS capabilities

Member States shall ensure that, by 1 January 2019 transport-type State aircraft with a maximum certified take-off mass exceeding 5 700 kg or having a maximum cruising true airspeed capability greater than 250 knots, operating IFR/GAT flights in European airspace are equipped with appropriate ADS-B, Mode S ELS and EHS avionic configurations.

Member States shall communicate to the Commission by 1 July 2016 at the latest the list of State aircraft that cannot be equipped with secondary surveillance radar transponders that comply with the Mode S ELS requirements, together with the justification for non-equipage.



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Member States shall communicate to the Commission by 1 July 2018 the list of transport-type State aircraft with a maximum certified take-off mass exceeding 5 700 kg or having a maximum cruising true airspeed capability greater than 250 knots, that cannot be equipped with appropriate ADS-B and Mode S EHS avionic configurations together with the justification for non-equipage.

31 Dec. 2017

31 Dec. 2018

2 Jan. 2025

Member States shall communicate to the European Commission by 31 December 2017 at the latest, those approach areas where air traffic services are provided by military units or under military supervision and when procurement constraints prevent compliance to the ACID Implementation Regulation. The date of compliance for these areas shall not be later than 2 January 2025.

The Commission, in consultation with the Network Manager (Eurocontrol) may review the exemptions communicated that could have a significant impact on the EATMN. The decision of the European Commission shall be communicated before 31 December 2018.

Implementing Regulation on aircraft identification for surveillance for the single European sky

and


2 Jan. 2020 ANSPs shall ensure that, by 2nd January 2020 the cooperative surveillance chain has the necessary capability to allow them to establish individual aircraft identification using the downlinked aircraft identification feature

Implementing Regulation on aircraft identification for surveillance for the single European sky

Table 1: Key Dates Contained in Published European Commission Implementing Regulations

2.2 Avionics Supporting Surveillance As an aircraft flies within the airspace of a number of States the avionics it carries on board becomes the common-denominator across the European Surveillance infrastructure and is needed to ensure seamless operation of the aircraft throughout European airspace. Increasing the capabilities of transponders and their supporting avionics enables ANSPs on the ground to exploit new, cheaper and more capable technologies, to process increasing air traffic densities and to conduct more demanding separation applications whilst improving safety.

The migration of surveillance functionalities from the ground to the aircraft represents a fundamental aspect in which the scope and the manner of how surveillance is undertaken and how it will evolve in the coming years. Timely coordination with civilian and State aircraft operators is necessary to prevent significant delays for full implementation of such functionalities.

2.2.1 Equipage Requirements

2.2.1.1 Current requirements In a number of States in Core Europe mandates have been established that have led to the replacement of the conventional SSR Mode A/C systems carried on board aircraft by SSR Mode S avionics. In certain transponder mandatory zones these requirements can also extend to Mode A/C or Mode S ELS equipage for flights conducted as VFR.

In a number of States in Core Europe mandates have been established that require SSR Mode S Enhanced Surveillance systems to be carried on board aircraft whose weight or speed exceed specified thresholds (and which are capable of being upgraded to Mode S EHS).


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As the majority of European flights are conducted within the Core Area a significant percentage of aircraft operating in Europe are thus already equipped with Mode S ELS and, for aircraft exceeding specified weight and speed criteria (and which are capable of being upgraded) with Mode S EHS.

The upgrade of avionics to the more demanding Mode S requirements was and still is not without technical issues (especially for State aircraft). Indeed a number of design anomalies have been identified and despite rectification means being available the issue remains unresolved on a significant number of aircraft. As a consequence, some Mode S ground-stations continue to be operated in a sub-optimal manner (with respect to RF) in order to ensure that anomalous aircraft are correctly detected.

The publication of European Commission Implementing Regulation1207/2011 (Ref Doc 5) supplements existing (locally issued) Mode S carriage requirements and introduces European wide requirements for aircraft with a maximum Take Off Mass greater than 5700kg or a Maximum Cruising True Air Speed greater than 250 knots to be appropriately configured with ADS-B 1090MHz Extended Squitter (ES) and Mode S (ELS and EHS) avionics. However this implementing regulation only applies the EHS and ADS-B Out requirements to a sub-set of aircraft (those exceeding defined weight and speed thresholds, including State aircraft). However, the use of ADS-B is optimised when 100% of the aircraft in a defined volume of airspace are equipped. Additional legislation is therefore required to support the operational introduction of standard ADS-B applications. This would be achieved either through the segregation of airspace or ADS-B equipage on all aircraft. The inclusion of such requirements through a European wide Implementing Rule could be considered in the longer term.

2.2.1.2 Near Future Requirements The avionics specified in the above regulation brings improvements to the quality of surveillance and paves the way for airborne self assured separation. The availability of Aircraft Derived Data (ADD) on the ground, such as available through Mode S EHS, WAM and ADS-B, has also being demonstrated to bring significant safety benefits.

It is recognised that changes to an aircraft avionics places a cost burden on the aircraft operator however the introduction of Mode S and ADS-B ES functionalities is considered a necessary measure to support future ATM.

SESAR WP 9.24 studies the possibilities to implement ADS-B IN/OUT functions on board all types of State aircraft by reutilisation of existing on board equipage to the maximum intend possible.

The development of suitable ADS-B avionics for use with smaller or all aircraft is to be expedited.

2.2.1.3 Extension to Avionic Capabilities The following should be considered within the ATM Masterplan updates as they will impact upon the time-scales for the availability of additional aircraft derived data and may be constrained by developments and deployment of transponder modulation techniques (and, where necessary, adaptations to ground-stations) that may be necessary to support the increased capacity demands. Deployment should be dependent upon a proven cost-benefit case.

2.2.1.3.1 Aircraft Derived Data

Whilst Implementing Regulation1207/2011 (Ref Doc 5) took into account and, when published, specifications such as CS-ACNS (Ref Doc 14) will take into account the ADD requirements of SESAR Operational Improvements (OIs) that were sufficiently mature for their inclusion it may be that the further development of some SESAR OIs necessitates the provision of further ADDs.

The down-linking of additional data such as meteorological data, runway friction, wake vortex information or even details of the VHF voice frequency that is being used could also be considered. However whilst it is feasible to extend the number of parameters that can be broadcast it is necessary that any further additions to the list of parameters should be carefully managed to minimise the cost burden on aircraft operators and the ability of the RF environment to support additional transmissions.


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2.2.1.3.2 Improved Modulation Techniques

The transmission of data from aircraft was, until fairly recently, restricted to identity and height information only. The introduction of surveillance techniques such as Mode S Enhanced Surveillance and ADS-B has enabled the transmission of additional data items from the aircraft. A list of those data items broadcast through Mode S EHS and ADS-B is provided in Appendix B.1. These data items address the requirements of surveillance applications that were sufficiently mature at the time of the production of the appropriate design specifications however they represent only a sub-set of the data that is available on board the aircraft. The set of data items was restricted as their broadcast uses up valuable RF spectrum.

The development of new applications may necessitate or may benefit from the transmission of further data from an aircraft. To avoid placing further demands upon the RF spectrum efficiencies need to be obtained in the manner in which additional data items are relayed to the ground. If proven to be backwardly compatible one such technique is to introduce phase modulation ‘on-top’ of the existing 1090 MHz Amplitude Modulated signals.

The feasibility, design and impact of the introduction of such a technique needs to be further assessed and is one area for consideration within the future SESAR ATM Masterplan.

2.2.1.3.3 ACAS and Hybrid Surveillance

ACAS transmissions have been seen to contribute significantly to the RF environment (accounting for up to 50% of the 1030/1090 MHz signals in airspace with high traffic densities). SESAR WP 9.47 is addressing this matter and techniques such as hybrid surveillance (in which ACAS processing exploits the ADS-B transmissions from aircraft) are anticipated to provide significant improvements.

The upgrade to and introduction of Hybrid ACAS will necessitate avionic changes. It is important to note that benefits from such techniques would be accrued from the first aircraft. The rate of introduction could thus be phased depending upon the degree of RF congestion to be addressed.

2.2.1.4 Utilisation of ADS-B In and the Delegation of Responsibilities The publication of European Commission Implementing Regulation1207/2011 (Ref Doc 5) introduces avionic capabilities that pave the way to ADS-B In and a range of new surveillance separation applications that improves air-crews situational awareness and facilitates new modes of aircraft separation.

Initial ADS-B ATSAW operations in European airspace rely upon the voluntary equipage of an aircraft with ADS-B In avionics. It is anticipated that ADS-B In will in the near term remain voluntary however some form of legislative instrument to extend operations may be introduced in the longer term when benefits are proven and required levels of equipage cannot be achieved through voluntary means.


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2.3 Development Status of Surveillance Techniques

2.3.1 General Surveillance information can be provided using a range of different techniques. Not so long ago, the surveillance infrastructure was composed of mono-pulse secondary surveillance radar (SSR), SSR Mode-S and primary surveillance radars (PSRs). Recently, however, technological developments such as automatic dependent surveillance–broadcast (ADS-B) and wide-area multilateration (WAM) have reached maturity for operational deployment. On-going developments in MSPSR and Satellite ADS-B have the potential to offer even further choice but need further specification, development and validation.

As new technologies evolve others become obsolete – if not in design but in terms of availability of components and cost effective repairs. A typical life cycle for a civil surveillance sensor is in the region of 12-15 years (although may be significantly longer for military sensors). The efficiency of older type SSRs may not match that of newer technologies in terms of running costs, RF occupancy and also the potential for improved controller productivity. Mode A/C Secondary Surveillance Radar (SSR) was, for many years, the key enabler for air-ground surveillance is however now in decline.

The techniques selected by an Air Navigation Service Provider (ANSP) will depend upon a variety of factors including avionic equipage of aircraft flying in the airspace, the operations performed, legacy systems, economics and the nature of the terrain and environment. This section provides an assessment of current surveillance techniques and an indication of when emerging techniques will become available.

The introduction of new surveillance techniques into an existing architecture needs careful planning – not only to ensure that the corresponding equipage is available on board the aircraft but that the rest of the ATM infrastructure has the means to exploit the data.

Numerous activities have yet to be performed to analyse potential benefits of MSPSR, Composite solutions (such as ADS-B and WAM) and also Satellite ADS-B. If found to have potential the next step would be to develop operational requirements and functional specifications – these tasks should therefore be considered for inclusion within the Masterplan.

2.3.2 Independent Cooperative Surveillance Techniques Independent cooperative surveillance requires airborne avionic (SSR transponder) to provide independent aircraft horizontal position. It also provides aircraft pressure altitude, aircraft identity and other aircraft parameters depending on SSR transponder capability. The 1030MHz frequency is used for uplink interrogations and 1090MHz is used for the downlink transmissions.

2.3.2.1 SSR Mode A/C and Mode S SSR Mode A/C radars, both sliding window and mono-pulse designed, formed the basis of ATM surveillance for many years however they are now being phased out due to the availability of superior alternatives and their inability to meet the increasing needs of a more demanding environment and the requirements for use of Aircraft Identification and other aircraft derived data (see European Commission Implementing Regulation Numbers 1206/2011 (Ref Doc 6) and 1207/2011 (Ref Doc 5).

SSR Mode S techniques and technologies supporting both SSR Mode S Elementary Surveillance (ELS) and Enhanced Surveillance (EHS) are considered as proven and are already subject to wide-spread deployment in core-Europe.

The manner of operation of civil / military Mode S ground-stations is more efficient if the stations are operated in a cluster.

As for all other cooperative surveillance techniques the operation of SSR Mode S is dependent upon correct functioning of the avionics. Whilst the Mode A/C transponder was a relatively simple design that had remained relatively unchanged for many years there were numerous avionic anomalies discovered during the operational deployment of Mode S in Europe. The resolution of these issues, which in some cases remains on-going even some years after the identification of the anomaly, has delayed the point in which the benefits of the significant ground and air deployments.


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2.3.2.2 Wide Area Multilateration Wide Area Multilateration (WAM), in both its active and passive forms, can be considered as a proven surveillance technique that is being increasingly deployed throughout Europe and across the world.

WAM groundstation receivers can, and often do, incorporate ADS-B Extended Squitter (ES) receiver functionality as a stand-alone channel. In 2012 EUROCAE WG51 SG 4 was established to support the exploitation of the synergies and potential benefits of merging the two techniques, cross sharing of data and common utilisation of hardware. The deployment of an infrastructure based upon a composite ADS-B/WAM configuration thus provides an independent position of the aircraft based upon multilateration techniques and also a dependent position based upon ADS-B ES.

2.3.2.3 Summary The following table summarises the development status of Independent Cooperative Surveillance:

Technique Development status

and Operational Availability

Comments

Mode A/C SSR (Sliding window and Mono-pulse

variants)

Available but to be phased out as soon as operationally appropriate.

Being phased out due to its RF inefficiency and poor performance in high traffic density airspace. Not compatible with the ACID Implementation Regulation requirements.

Mode S SSR

Available. Ground system specification available.

Provides aircraft derived data (ELS & EHS) and superior quality of surveillance data when compared against SSR Mode A/C. Increasing deployment foreseen in short term however reduction in longer term due to ADS-B deployment. Mode S SSR systems will continue to be deployed e.g. when economically justified or where terrain constraints preclude the use of WAM.

Wide Area Multilateration

Available. Ground system specification available.

Provides aircraft derived data (ELS & EHS) and superior performance compared against SSR Mode A/C. Increasing deployment foreseen in short term however stabilising in longer term due to ADS-B availability. Passive & active configurations available. Combined/composite ADS-B and WAM deployments exploit the synergies between the two techniques.

Table 2: Summary of the Development Status of Independent Cooperative Surveillance Techniques

2.3.3 Dependent Cooperative Surveillance Techniques Dependent cooperative surveillance is based on aircraft/vehicle broadcasting their position (calculated by on-board GNSS system), altitude, identity and other parameters via the 1090 MHz SSR band.

ADS-B is recognized within the ATM Masterplan as one of the important enablers of several of the ATM operational concept components (See section 5). It requires suitable airborne equipage and can support 3/5NM separation minima.

ADS-B on 1090MHz is recognised as the medium for international use.

2.3.3.1 ADS-B Out The validation of the ADS-B surveillance technique for a range of initial applications can be considered as complete with the results being incorporated into specifications defining both the avionics and the ground-station components.

The ADS-B Out applications currently foreseen include:

• ADS-B in Non Radar Airspace (ADS-B NRA)

• ADS-B in Radar Airspace (ADS-B RAD)

• ADS-B for Airport Surface Surveillance (ADS-B APT)

• ADS-B for Aircraft-Derived Data (ADS-B ADD)


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Further development upon more demanding ATSAW and ASAS type separation applications is underway (See SESAR WP 5.6.6).

2.3.3.2 ADS-B In In parallel with the widespread deployment of ADS-B Out transponder functionality, airborne surveillance applications are being deployed which directly support airspace users. This requires aircraft to be equipped with avionic systems (including a traffic computer and cockpit display of traffic information) that are able to use the surveillance information broadcast by other aircraft or airport surface vehicles. This is known as ADS-B IN and enables various applications such as ATSAW, spacing, separation and self-separation.

The ADS-B In applications currently foreseen include:

• ATSAW In-Trail Procedure in oceanic airspace (ATSAW ITP)

• ATSAW Visual Separation in Approach (ATSAW VSA)

• ATSAW during Flight Operations (ATSAW AIRB)

• ATSAW on the Airport Surface (ATSAW SURF)

• Interval Management (IM)

• Indicators and Alerts (IA)

Furthermore, future airborne surveillance applications are being standardised or investigated by SESAR at R&D level thus paving the way for the so-called new separation modes spacing, separation and self-separation.

2.3.3.3 Satellite ADS-B The concept of satellite ADS-B surveillance, a technique in which the 1090MHz signals broadcast from an aircraft is received by a satellite before on-ward transmission back to a ground-station, is starting to emerge. The technique needs to be assessed to see if it could bring sufficient benefits in European airspace of low density or oceanic airspace justify the expenditure.

Subject to further development the use of ADS-B receivers located on low Earth orbit satellites could provide a means for ATM surveillance in volumes of airspace, initially in regions such as oceanic or remote areas, in which it is currently difficult or even impossible to provide through conventional ground based systems.

Oceanic airspace (or remote) is currently using ADS-C to support separation provisions however satellite ADS-B systems, such as the Iridium-based system that is currently being assessed by the FAA and others, could be an alternative means to provide surveillance cover e.g. in oceanic or low density regions.

The technical assessments being conducted by the FAA will address the integration with other enabling technologies (Communications and Navigation) as well as studies to evaluate technical alternatives. These will be coupled with a regional or state business case to determine whether to proceed with this technology for implementation in a longer term timeframe. If the business case and operational needs can be met through such a technique then this has the potential to complement or replace the surveillance services currently achieved using ADS-C in Phase 2 of this roadmap. This subject is not included in the initial version of the ATM Masterplan (Ref Doc 2) but is a candidate for further analysis.

This potential should be considered for inclusion in subsequent SESAR activities and ATM Masterplan documentation.


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2.3.3.4 Summary of Cooperative Dependent Surveillan ce The following table summarises the development status of Dependent Cooperative Surveillance: Technique Development status


Comments

ADS-B OUT

Standards available. Operations in NRA ongoing. Operations in high-density areas supported by regional mandates on aircraft equipage

Provides cost effective and efficient means of surveillance supporting a wide range of new applications proposed within the SESAR concept. The technologies are ready. Initial Operational Capability (IOC) is now achieved. Regarding Full Operational capability, (FOC) the main constraint of deployment of appropriate avionics is addressed by the relevant mandates worldwide. Widespread use in dense airspace (i.e. FOC) is expected from 2020 i.e. end of Phase 1.

ADS-B IN

Standards for ATSAW are available and operations have started. Other applications (spacing) being standardised. Next applications (separation and self separation are at R&D level)

Enables airborne surveillance applications; ATSAW, spacing, separation and self separation. Initial deployment of ADS-B IN is currently ongoing and is conducted on a voluntary basis with increasing deployment encouraged through benefits from new applications.

ADS-C

Available.

The long term surveillance service aspects of ADS-C could potentially be influenced by ADS-B through satellite after 2020 or, subject to aircraft equipage by ADS-B In.

Satellite ADS-B

Under assessment /development.

The subject was initiated post the publication of SESAR ATM Masterplan v1. No feasibility studies have been published although the FAA is reported to be investigating further.

Table 3: Summary of the Development Status of the Dependent Cooperative Surveillance Technique


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2.3.4 Independent Non-Cooperative Surveillance Independent non-cooperative surveillance does not rely on any form of airborne avionics. They are used in order to detect, and can be used to provide a separation service to, aircraft with inoperative transponder (faulty or shutdown) or aircraft without a transponder.

The detection of non-cooperative aircraft will be performed, in volumes of airspace where it is deemed operationally necessary, using non-cooperative surveillance techniques. In addition to supporting ATC operations in airspace where the carriage of an SSR transponder is not mandatory this will be used to mitigate against avionic failures and support the detection of aircraft intruding, accidentally or deliberately, into controlled airspace.

2.3.4.1 Mono-Static PSR Mono-static conventional PSR radars have existed for many years. Developments regarding improved driver stages such as solid state, improved signal processing (with improved clutter rejection capabilities) and improved antenna design continue and have led to significant improvements in the performance and capabilities of conventional systems however the spectrum demands and impediments due to mono-static deployments (e.g. rejection of clutter originating from wind-farms) and the detection of low RCS targets constrain the benefits of such systems.

Due to high costs of ‘traditional’ mono-static PSR techniques and increasingly demanding spectrum requirements, this requirement could, subject to successful development and validation, be met more efficiently through the use of Multi-Static PSR (MSPSR) systems.

In addition to supporting ATC operations, non-cooperative surveillance techniques also support national security and air defence tasks. Thus there is a continuing need for non-cooperative surveillance systems. Both Air Defence and Civilian/State ANSPs will continue to rely upon ‘traditional’ PSR technologies until a suitable replacement, such as active MSPSR, is sufficiently mature.

2.3.4.2 Multi-Static PSR Whilst spectrum charging, the mandatory carriage of transponders and a need for cost efficiencies will drive a reduction in the use of conventional PSR it is anticipated that some form of non-cooperative surveillance technique will be retained where deemed to be operationally necessary to support civil and/or military applications. It is likely that Multi-Static Primary Surveillance Radar (MSPSR) techniques which are capable of addressing issues facing conventional PSR will be developed and deployed.

The MSPSR technique is a new type of independent non-cooperative surveillance currently under development. (The technique was initially developed as a passive system relying upon transmitters of opportunity to support defence applications rather than for ATC applications. Further development is now required to ensure that the technique, in either passive or active form, is able to meet the operational needs of ATC).

Whilst MSPSR capable of supporting civilian/military ATC applications is not yet developed numerous feasibility studies and several passive demonstrators have been conducted and these all support the consideration that the technique is likely to be cost effective, spectrum efficient and capable of high performance.

MSPSR technology consists of using several transmitters and receivers in a multi-static configuration to detect aircraft. It should be noted that the transmitters used as a source signal could in fact be ‘transmitters of opportunity’ i.e. transmitters used for other purposes such as broadcasting DVB-T (Digital Video Broadcasting -Terrestrial) signals. However this approach may introduce significant restrictions in the maximum height detection / vertical coverage capabilities and it is therefore only likely to be used in such a configuration to provide surveillance in the vicinity of airports or aerodromes rather than TMA coverage. (This restriction is due to the fact that the transmitters of opportunity are deliberately transmitting their signals towards the ground rather than into the air). Note: Passive MSPSR is also commonly referred to as Passive Coherent Location – PCL.

The use of Passive MSPSR / PCL, especially for covert type military applications and for civilian ATC applications where the currently anticipated height restrictions do not compromise operational requirements, remains viable. Active MSPSR may have the potential to offer many significant


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improvements in terms of performance, cost, reliability etc. however does require dedicated RF spectrum.

The results of initial feasibility studies into MSPSR techniques (See Ref docs 16, 17 and 25) point to:

• Potential savings on spectrum usage in comparison to today’s civil PSR systems, a feature that is interesting following the declaration of a number of State authorities to introduce spectrum charging mechanisms

• Performance capabilities that would support the detection of aircraft with low radar cross sections – such as small aircraft fabricated using composite materials.

Subject to operational requirements the MSPSR systems could also be configured to provide an indication of the height of a non-cooperative aircraft. In addition, it could provide an efficient means of addressing a problem particularly evident on current mono-static PSR – namely the radar signal clutter resulting from wind farms.

Where operationally necessary the mono-static non-cooperative technique such as PSR could be used to:

• Provide long range En Route coverage (and short range TMA coverage when needed) in an environment without visibility issues,

• Provide coverage in areas where terrain issues or restrictions (such as coastal or access conditions) would result in a complex MSPSR site infrastructure.

Provided suitable deployment sites are available1 multi-static non cooperative techniques (i.e. MSPSR and PCL) could be used to:

• Complement mono-static technologies. For example, multi-static systems may provide a suitable means fill coverage gaps such as:

o Coverage gaps at low altitude due to the distance to the airport, where the mono-static sensor is deployed,

o Coverage gap due to the masking of valleys, mountains and man-made obstacles,

o Coverage gap between two mono-static sensors.

• Provide Surveillance over wide areas for En Route and TMA purposes, particularly when a specific requirement on low altitude detection exists.

• Provide a locally improved performance if necessary (higher data renewal rate and additional locally operational availability, indication of aircraft height – subject to operational requirements, improved resilience against clutter stemming from windfarms). This local performance improvement could be useful to support complex trajectory management such as parallel runways or the management of complex air-routes,

• Provide coverage in areas with high spectrum constraints (i.e. spectrum charging, high garbling, low decode rate…) and using PCL in areas where:

o Traditional technologies would prove to be too expensive,

o Suitable opportunity transmitters are available with a sufficient operational availability (e.g. through agreement with the owners of the opportunity transmitters).

It is possible that configuring such non-cooperative multi-static technologies in common hardware configurations with cooperative surveillance systems could bring benefits such as a reduced number of standalone stations of distributed systems through the use of collocated technologies. (EUROCAE WG51 SG4 was established in 2012 to address a similar approach specifying the requirements of a ‘Composite Surveillance System’ bringing together dependent cooperative surveillance (ADS-B) and independent cooperative surveillance (WAM) ground-station components).

1 To provide active or passive coverage in areas where several deployment sites are available - at least 3 or more sites with good line of sights are required. The infrastructure of the sites is then ‘light’ for each site,


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An initial step that needs to be performed to ensure the future developments are appropriate is to assess the true operational need for non-cooperative systems. The technical development could then be focussed upon achieving defined objectives.

An MSPSR system is expected to be available for validation in the near future with an anticipated availability date between 2015 to 2020.

2.3.4.3 Summary of Independent Non-Cooperative Surv eillance The following table summarises the status of Non-Cooperative Surveillance:

Technique Development status


Comments

Mono-Static PSR

Available. Under spectrum pressure. Current conventional PSR have not been designed to and therefore might not be able to detect future aircraft (e.g. RPA) that are expected to exhibit a lower radar cross section. Technological developments support improved transmitter technology e.g. Solid State and signal processing capabilities. Development of Mono-static PSR tracker techniques is focussed upon providing acceptable detection of aircraft flying over wind-farms and resolving dynamic clutter interference.

MSPSR (Passive) /

PCL

Technical feasibility proven. Operational requirements for civil and military applications to be developed.

Low altitude surveillance could be achieved by exploiting transmitters of opportunity. No direct spectrum consumption but in return, depends on the availability of opportunity transmitters. Resilient to wind farm and general clutter.

MSPSR (Active)

Technical feasibility proven. Operational requirements for civil and military applications to be developed. Initial operational availability and deployment expected within Phase 1.

R&D on MSPSR is expected to lead to initial commercially available systems within the timescales of Phase 1 of this roadmap. Low altitude surveillance could be achieved by exploiting transmitters of opportunity. Spectrum requirements however potentially efficient even in active configurations when compared to conventional PSR. Resilient to wind farm and general clutter. Active MSPSR (in which dedicated transmitters are part of the MSPSR system) could meet more demanding performance requirements e.g. reduced RCS, 3D height declaration, more frequent data update rates etc. subject to development and validation.

Table 4: Summary of Development Status of Independent Non-Cooperative Surveillance Techniques

2.3.5 Ground Data Fusion Surveillance is likely to be provided using a combination of different surveillance techniques. This requires an appropriate function to provide a seamless interface between the surveillance sensors, each with specific characteristics, and the end users (controller and tools). Current mechanisms such as data fusion or multi sensor trackers will address this need and such multi-sensor fusion systems are already available.


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Following the fusion of the surveillance data from various sources, the ATC and other Users will receive and use multi-sensor tracks and thus be unaware of the specific source of the surveillance data. The data presented shall be considered by ATC to be fit for purpose with the systems integrity monitoring being used to filter out erroneous data.

2.4 Deployment Status of the Surveillance Infrastru cture

2.4.1 The Current European Surveillance Infrastructure The Surveillance infrastructure for European ANSP’s is currently achieved through the use of sliding window SSRs, Mono-pulse SSR, SSR Mode-S (Elementary and Enhanced) and Primary Surveillance Radars (PSR). SSR Mode S is extensively deployed across central Europe. In niche areas, where the technique brings specific benefits, Wide Area Multilateration is also in operational use.

The current surveillance infrastructure meets current needs. However, as we have seen elsewhere in this paper, the operational environment is changing and there is a need to plan for the future and exploit changes to meet operational challenges.

2.4.1.1 Cooperative Surveillance Systems

2.4.1.1.1 SSR Mode A/C

SSR systems have formed the backbone of ATC for many years and provide controllers with the height and an identity of co-operative aircraft. Such systems have evolved from sliding window processors through mono-pulse processors to Mode S to meet increased traffic densities and to overcome problems associated with garbling and interference.

SSR systems that employ the older style of Sliding Window processing are increasingly seen as inefficient and responsible for a disproportionate usage of the 1030/1090 MHz RF environment. Such systems only meet lower performance capabilities when considered against more modern mono-pulse and Mode S SSR systems. SSR Mode A/C systems that use monopulse signal processing are less prone to losses of detection and azimuth shifts when replies from two aircraft partially overlap in azimuth.

Monopulse secondary surveillance radar (MSSR) is an improved version of the classic SSR technique aimed at reducing Garbling and the False Replies Unsynchronized with the Interrogation Transmissions or simply FRUIT.

The MSSR replaced most of the existing SSRs by the 90s and its accuracy provided for a reduction of separation minima in en-route ATC from 10 nautical miles to 5 nautical miles however a number of the older systems, which are inefficient from an RF perspective are not yet replaced – particularly in the Military due to funding issues and lengthy procurement procedures.

It should be noted that SSR Mode A/C systems cannot be used to achieve the requirements of the ACID and SPI Implementation Regulations (see European Commission Implementing Regulation Numbers 1206/2011 (Ref Doc 6) and 1207/2011 (Ref Doc 5)).

2.4.1.1.2 SSR Mode S

SSR Mode S groundstations are now deployed across many European states.

In addition to resolving garbling issues and providing improved quality surveillance data the SSR Mode S Elementary Surveillance systems that are being used operationally provide ANSPs with a means to achieve the requirements of the ACID Implementation Regulations (Ref Doc 6).

SSR Mode S Enhanced Surveillance is extensively deployed in Core European states and provides the air traffic controller, and his support tools such as STCA and MTCD, with additional data items pertaining to the short term intent of the aircraft.

2.4.1.1.3 Wide Area Multilateration

Multilateration systems were initially deployed on main airports for the surveillance of aircraft on the surface. The technique is now deployed to provide surveillance over a larger geographical area. This


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is known as Wide Area Multilateration system (WAM). The deployment of such systems has taken place in many areas of Europe, providing surveillance in volumes of airspace where other forms of conventional surveillance were neither viable nor cost effective.

After addressing those niche areas where WAM offered clear advantages, ANSP’s have continued to deploy WAM as a replacement to conventional cooperative surveillance solutions where beneficial. An area in which WAM offers a significant advantage over ‘rotating’ surveillance sensors is the possibility for a much increased update rate. Such functionality is especially beneficial to ATC monitoring manoeuvres during approach.

Many WAM groundstations have integrated ADS-B functionality and are thus capable of supporting the future evolution towards ADS-B.

When deploying active WAM systems care should be taken to ensure that their 1030 MHz transmissions are the minimum required to support the applications being performed.

The deployment of a WAM system does not necessarily follow the same procurement model as for mono-static systems. Due to the iterative nature that follows from the process of defining the performance and coverage requirements and the subsequent mapping of these through the selection of appropriate sites it is vital that WAM manufacturers are involved at an early stage in the procurement process.

2.4.1.1.4 ADS-B

Automatic Dependent Surveillance –Broadcast (ADS-B) has reached a sufficient maturity level for operational deployment in non radar areas (NRA) and will shortly enter into operational use in Europe. It is currently being put into operation as sole means of Surveillance in certain airspaces of Norway, Iceland and together with WAM in the Netherlands and Portugal. ADS-B Out NRA is currently operational in Australia and Canada/Hudson Bay.

In addition, as detailed above, several other countries2 have deployed or are currently deploying WAM infrastructure and are expected to make use of the inherent ADS-B capability as soon as suitably equipped aircraft begin to present themselves. The European Commission Implementing Regulation No 1207/2011 (Ref Doc 5) will accelerate this process.

The operational use of ADS-B in the Non-Radar Airspace (ADS-B NRA) context means avionics compliant to at least the requirements of Eurocae ED102 (Ref Doc 19) with certification based on EASA AMC 20-24 certification material. Ground components are to be compliant with ED129 (Ref Doc 20). See also ED126 (Ref Doc 21).

The operational use of ADS-B in the Radar Airspace (ADS-B RAD)) context means avionics compliant to at least the requirements of Eurocae ED102A (Ref Doc 13) and ground components compliant with ED129A (Expected title - not yet published). See also ED161 (Ref Doc 22).

The deployment of ADS-B for the other ADS-B Out applications identified in 2.3.3.1 (including high-density areas), in accordance with published standards, is being driven by legislation - in Europe by the Commission Implementing Regulation (EU) No 1207/2011 laying down requirements for the performance and the interoperability of surveillance for the single European sky (Ref Doc 5). Additional local mandates to establish ADS-B equipage of aircraft below the specified weight or speed thresholds may be required where 100% equipage is necessary to support the surveillance applications being performed.

The first operational use of ADS-B In applications in Europe were the ATSAW during Flight Operations (ATSAW AIRB) and the ATSAW In Trail Procedure (ITP) over N. Atlantic (Shanwick FIR and Reykjavik FIR). ADS-B ATSAW is currently operational in US and elsewhere.

The initial deployment is supported by the availability of ADS-B Out operationally approved aircraft due to the operations in Hudson Bay and Australia, as well as the EUROCONTROL CASCADE Pioneer project. The upgrade of avionics and cockpit systems for ATSAW is currently voluntary and will be driven by the relevant benefits.

2 Austria, Bulgaria, Cyprus, the Czech Republic, Greece, Latvia, Germany, Romania, Spain, Sweden and UK


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Furthermore, future Airborne Surveillance applications are being standardised or investigated by SESAR at R&D level thus paving the way for the so-called new separation modes spacing, separation and self-separation.

2.4.1.2 Non-Cooperative Surveillance PSRs are generally used to provide safety mitigation against failures in an SSR system and for the detection of non-cooperative aircraft in TMA and, where required, also in En-Route airspace. In lower density airspace they are also used to provide a separation service – with identification of the aircraft established and maintained through voice communications. The current ‘Surveillance Standard’ document states that PSRs are required for use in major TMAs and in En-Route airspace where required.

In the Military Non-cooperative aircraft must always be detected for safety and security reasons. For military ATC operations Independent Non-Cooperative surveillance is of paramount importance and not only for Air Defence (AD) operations for which security is the major task. In addition, military ATC PSR need to be able to detect and track aircraft flying at lower altitudes with much higher manoeuvring capabilities (climb-/descent-/turn-rates) than civil airliners.

PSRs used for ATC are normally 2D (Range and Azimuth) systems i.e. the height of the aircraft is obtained from other sources (voice communications or SSR). Whilst 3D (Range, Azimuth and Height) PSRs are used in Air Defence networks the complexity and cost of such systems means that they are not suited for general ATC purposes.

No uniform descriptions of operational requirements are published for PSR use.

The performance achieved by a PSR is very dependent upon the local environment (terrain, clutter, weather) and the system capabilities. Modern signal processing and mono-radar trackers are capable of extracting signal returns from aircraft in an increasingly dense clutter environment. In some European nations Military Authorities are still operating legacy analogue PSR for which this increasing clutter is causing high impacts.

For both, modern and legacy PSR the performance achieved needs to be assessed in the light of an adapting environment – one in which new sources of clutter are becoming evident (e.g. wind farms and GSM encroachment into radar frequency bands) and targets may be becoming smaller (aircraft radar cross sections may be reducing due to the use of composite materials in their manufacture).

2.4.1.3 Numbers and Age of Sensors

2.4.1.3.1 Numbers of Surveillance Sensors

There are estimated to be over 500 SSR type radars in operation in ECAC states. (The following table includes those Mode S radars operated by military authorities and the number of conventional SSR systems they may operate. The location of military SSR systems is not included on the Google Earth presentations).

Operator type Total

Airport ANSP 3

ANSP 200

Military 146

Total 349

Table 5: Secondary surveillance radars (Mode A/C) installations


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Table 6: Secondary surveillance radar (Mode S) installations3

Most civil SSRs are operated by air navigation service providers (ANSP). A few are operated by private airport companies which carry out their own ATC and a number are commercially owned, mostly by radar equipment manufacturers. There are no technical reasons behind the disparity in the numbers of Mode A/C SSRs vs. Mode S that are operated by airports or ANSP’s. In reality it is likely to be a compound rational including the age of the sensors and the fact that larger ANSP’s committed to Mode S and upgraded in a defined manner.

24 Mode S SSR are operationally working in cluster, there are currently 4 clusters in operation in the Netherlands and in Germany.

Details of some 156 civil PSR radars are included in the database. These are either configured as standalone radars or co-mounted with SSR systems. (Partial details for a number of further PSR radars in the UK are contained in the database but as the information is incomplete the radars are not included below).

There are also a significant number of military SSR sensors – only some of which are identified in the tables above.

From recent assessments of the degree of overlapping surveillance coverage it appears that there is a significant degree of duplication of surveillance coverage.

This is especially evident at higher altitudes but also extends to lower altitudes. The degree of overlap is often driven by very low altitude surveillance coverage requirements and as the assessment of such local needs is beyond the scope of this study they should be assessed on a local and wider vicinity basis. The degree of overlap is sufficiently high as to indicate that the system is sub-optimal and that a degree of rationalisation could be achieved through data sharing.

The RF environment in which the sensors operate is becoming denser and needs to be managed.

2.4.1.3.2 Ages of the Surveillance Sensors

Recent assessments indicate that there is a wide spread of ages of the deployed and operated surveillance sensors;

The oldest age declared in 32 years (Installation date 1979)

48 radars (either PSR or SSR) which are more than 20 years old

45 radars have a declared installation date in 2010.

The average age of a radar system is approximately 10 years. Thus there is a long working life left in the majority of the current European radar stock. Some 215 of the sensors are Mode S.

There are no Mode S radars older than 20 years.

Assuming an equipment life of 20 years, it is likely that a significant number of the radars, currently operated or in the course of implementation by ANSP’s and airports, could be in service to 2030 or beyond (assuming that they are taken out of service on the basis of age alone). By the end of 2017, the retrofit date detailed in European Commission Implementing Regulation 1207/2011 (See Ref Doc 5), over 70% of existing ANSP and airport radars are likely to be still in service (based upon a 20 year life-cycle).

Due to component obsolescence some manufacturers are offering mid-life upgrades whereby the signal processing stages of PSRs are replaced by more powerful systems using current processing. Mid-life updates are not reflected in the above information.

3 with an allocated interrogator code but may not all yet be operational

Operator type Total

Airport ANSP 9

ANSP 162

Military 44

Total 214


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These figures do not include those systems operated by the military ANSP’s for ATC purposes. Whilst many military systems have been upgraded to Mono-pulse SSR systems, or even Mode S configurations, it is to be noted that the Military continue to operate a significant number of conventional SSR systems and it is understood that a significant number are already over 20 years old. The presence of such systems can be detrimental to the efficiency and performance of the entire surveillance infrastructure. (It is recognised that some states are actively replacing such systems – e.g. many of the German systems that could be considered in such a category are already in the course of being replaced and this is certainly expected to reduce the density of 1030/1090 MHz transmissions). The rate of replacement will also be driven by European Commissions ACID Implementing Regulation 1206/2011 (see Ref Doc 6).

2.4.1.4 Data fusion Modern air traffic control systems use multi-sensor fusion processes to improve the quality of surveillance track data provided to air traffic controllers. This is achieved through either multi-sensor tracking or mosaicing.

Each surveillance sensor has different attributes, and a well designed multi-sensor fusion processor will take advantage of the strengths of each sensor, and use these to compensate where possible for the weaknesses of other sensors. It is important to note that some of the measures taken to mitigate the weaknesses of traditional radar sensors should not be applied to data from newer data sources (such as ADS-B) if those weaknesses are no longer a characteristic of the new data. Rather, the processing of each type of data in a multi-sensor fusion algorithm should be adapted to make best use of the actual performance of each of the data sources. Factors to be considered include accuracy, update rates, integrity (probability of false data), and amount of data provided (i.e. in addition to position, other aircraft information such as aircraft address, flight ID, vertical and horizontal velocities, bank angle, on ground or not, cleared flight level entered into the aircraft FMS, etc may be provided by some sensors, and these items should be used where they can improve performance).

Recent technological developments have resulted in a reduction in the costs for Multi-Sensor Tracker systems such as ARTAS and an increase in the number of such systems deployed.

Following the fusion of the surveillance data from various sources, the ATC and other Users will receive and use multi-sensor tracks and thus be unaware of the specific source of the surveillance data. The data presented shall be considered by ATC to be fit for purpose with the systems integrity monitoring being used to filter out erroneous data.

2.4.1.5 Data Transfer Surveillance data is transmitted over dedicated national aeronautical networks. However in some case networks are shared by neighbour countries.

The pan-European network service (PENS) is an international ground/ ground communications infrastructure jointly implemented by EUROCONTROL and the European ANSP’s in order to meet existing and future air traffic management (ATM) communication requirements, current needs for inter-ANSP information exchange and the needs within the SESAR programme for system-wide information management (SWIM), all of which need to be aligned with the Single European Sky Regulations and industry/ ICAO standards.

PENS provides a common Internet-protocol (IP) - based, managed network service across the European region to cover data and voice communications.

It will enable its users to exchange critical and common aeronautical information in a seamless and integrated manner, providing a highly cost-effective common infrastructure for the deployment of emerging ATM applications, which will significantly reduce the costly fragmented network services implemented using the outdated X.25 protocol, that is still in widespread use in some ANSP’s.

The PENS philosophy is based on the concept of sharing. All PENS users located at the same site can in fact share the same infrastructure in a secure way, providing substantial economies of scale, as the number of lines is optimised.

ASTERIX stands for All purpose STructured Eurocontrol surveillance Information eXchange and is an ATM Surveillance Data Binary Messaging Format which allows transmission of standardised surveillance information between any ATM system component. The ASTERIX data-format is the main format used for the transfer and sharing of surveillance information.


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3 Roadmap to the Surveillance Infrastructure of 203 0 The rationale behind the proposed roadmap is to present the evolution of a surveillance infrastructure capable of meeting the requirements stemming from SESAR and known and predicted changes to the operational requirements. The surveillance roadmap proposed in this paper details the foreseen availability of surveillance techniques and how they will be deployed within Europe over the next 20 years. It shows the evolution of the different surveillance techniques which may be used to support different surveillance applications used within TMA and En-Route airspace including ground based surveillance of aircraft and airborne surveillance of other aircraft. The key objectives the roadmap is designed to achieve include:

• The retention or deployment of a ground surveillance infrastructure supporting safety performance requirements:

o Achieved through the development (if necessary) and deployment of modern surveillance systems such as Mode S, WAM, ADS-B Out and MSPSR.

o Ground based surveillance in en-route and terminal areas with continuity of service being provided by at least 2 parallel layers of cooperative surveillance. Towards the end of Phase 1 it is anticipated that ADS-B RAD type applications will form a ‘stand-alone’ layer of surveillance to replace a single layer of cooperative surveillance. Where there is a need for non-cooperative surveillance to address safety or security concerns, it would initially be met by conventional PSRs although once developed and validated it could be fulfilled by Multi-static PSR (MSPSR) – where siting and system constraints support a technical and financially viable solution. The local surveillance infrastructure would be an optimal mix of the techniques to meet local requirements.

o In general, the optimal mix of the various surveillance techniques depends on the local environment, operational needs and business case from an overall ATM Network viewpoint. This will allow a smooth transition path from short term (radar like) surveillance system in a mixed equipage environment to the future high performance, rationalized and interoperable surveillance system.

• To enable the SESAR objectives for airborne surveillance including an improved situational awareness by aircrew of aircraft in their proximity and a phased introduction of ASAS applications:

o Achieved through the widespread deployment of ADS-B Out and ADS-B In. • To support a cost-efficient RF Spectrum strategy for surveillance including the long-term

viability of the 1090 MHz datalink, thus obviating the need for a costly and technically complex second data link:

o Achieved through a rationalisation of the surveillance infrastructure and the introduction of spectrum efficient mechanisms supporting ACAS and airborne and ground-based surveillance.

• To ensure the availability of surveillance techniques that support a reduction in the cost of providing surveillance services:

o Achieved through data sharing and the deployment of cost-efficient surveillance techniques.

These objectives have been evident for some years and as a consequence much work has already being undertaken to ensure that the route prescribed for the roadmap is already marked out. A key influence in the ‘route determination’ comes from the publication by the European Commission of Implementing Regulation No. 1207/2011 (see Ref Doc 5). The roadmap is split into two phases – today until 2020 and 2020 until 2030. The date of 2020 was chosen for the following reasons:

• It is approximately mid-way in the timescales, • It matches the end of Step 2 of the SESAR plan, • It is a few years after the dates detailed in European Commission Implementing Regulations

for widespread deployment of Mode S EHS and ADS-B avionics on-board aircraft conducting IFR/GAT flights in European airspace. (The few years later could serve as a period of consolidation - a buffer during which time initial deployment issues are resolved).


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The 2020 date does not reflect a key milestone or decision point in the gradual evolution of the surveillance infrastructure.

3.1 Target State description This section describes the ‘where do we want to be in 2030’ based upon SESAR and anticipated technological advances.

Surveillance must continue to adapt and improve in order to meet the increasing demands being placed upon it. The legislation identified in section Error! Reference source not found. introduces major milestones between 2012 and 2020 to pave the way for the infrastructure of 2030.

The Surveillance Infrastructure of the future is foreseen to be leaner and more efficient. ANSPs need to select the most appropriate of an increasing range of technologies that potentially offer improved performance, cost savings and coverage in difficult radar terrain supporting demanding operational environments. It is expected that this will be achieved by combining a layer of ADS-B with a layer of surveillance (provided either by SSR, SSR Mode S or WAM). Primary radar coverage will also be available, where required, possibly in the form of multi-static PSR (MSPSR). In addition to ground-based surveillance, ADS-B In will further enable the use of new airborne surveillance operational services including air traffic situational awareness (ATSAW), spacing, separation and self-separation.

The main changes are: • Migration of functionality from ground to air including the increased capability of aircrew to be

aware of surrounding traffic and to introduce new modes of aircraft separation based upon ADS-B In.

• Increasing choice of surveillance techniques for ground surveillance. • Widespread utilisation of ADS-B Out to support ADS-B Rad applications. • Increased utilisation of ADS-B In to support improved situational awareness and for

performing spacing, separation and self-separation applications. • Better In-band spectrum management • Change in operational environment, more aircraft equipped with cooperative surveillance,

smaller aircraft offering a reduced radar cross section, external spectrum pressure. Whilst the specific role of airborne collision avoidance systems in ATM is considered outside of the normal scope of ‘Surveillance’, it is felt appropriate, due to the extensive inter-dependencies, to present a section on the evolution of airborne surveillance in support of collision avoidance. The current situation is ACAS II as recently modified to TCAS V7.1 with the need for change being related to an adaptation to future ATM operations as well as a reduction of RF contribution. The following sections describe the route that is foreseen to be taken to reach that destination.

3.1.1 Principal Differences between the Current and Futur e Scenarios for Surveillance

The main changes or trends foreseen between the current and the manner in which surveillance services are provided in 2030 include:

• A migration of some surveillance functionality from the ground to the air. (See 3.1.1.1) o The airborne part of the surveillance system will become more important in the total

surveillance system and must be “future proof” and globally interoperable in order to support the various surveillance techniques which will be used.

• ANSPs will be able to select the most appropriate mix from an increasing portfolio of surveillance techniques that are or will be available to support ground-based surveillance. (See 3.1.1.2)

o Surveillance systems providing coverage tailored to specific volumes of airspace (rather than coverage over 360 degrees out to maximum instrumented range).

o Multi rather than Mono-Static deployments (such as ADS-B, WAM and MSPSR) o Obsolescence of old/existing technology and the availability of new technologies and

techniques offering the required performance and additional data at reduced cost. o ATC expectations that aircraft derived data, such as that made available through

ADS-B, Mode S EHS and WAM systems, is required to support their operations will influence the ANSPs selection process.


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o The use of aircraft derived data will be common-place with ATC expectations for such data to be readily available. (See 3.1.1.4.3)

o The different techniques will be mixed in order to obtain the best cost benefit depending on local constraints.

o The possible introduction of a new technique exploiting satellites to support separation services in remote and oceanic airspace. (See 3.1.1.4.3)

• The deployment of ADS-B In applications and appropriate avionics will support the increased capability of aircrew to be aware of surrounding traffic and facilitate new modes of aircraft separation.

• Adaptations to the use of RF Spectrum (See 3.1.1.3) o Better In-band spectrum management is required to support increasing traffic

densities. o The introduction of techniques and the implementation of appropriate means, related

to surveillance and ACAS, which improve the utilisation of the 1030/1090 MHz frequency band.

o Introduction of Spectrum Charging mechanisms. • Changes to the operational environment (See 3.1.1.4):

o Increasing traffic densities, o More aircraft equipped with surveillance transponders – in many cases providing

additional aircraft derived data to support ATC operations, o Increasing use of secondary and tertiary airports, o Accommodation of changes arising through the use of Functional Airspace Blocks, o Smaller aircraft offering a reduced radar cross section, o Inclusion of non-manned aircraft within controlled airspace and o External spectrum pressure.

• Support to the operational improvements stemming from initiatives such as SESAR. (See section 5)

• Increased deployment of transponders on small aircraft: o By 2030 it is anticipated that all aircraft, including non-powered VFR, Remotely

Piloted Aircraft (RPA) and military, will be equipped with cooperative surveillance avionics (light weight / low power surveillance transponders).

Whilst the specific role of ACAS, the airborne collision avoidance system in ATM is considered outside of the normal scope of ‘Surveillance’, it is felt appropriate, due to the extensive inter-dependencies, to reiterate that there is a need for a reduction in the 1030/1090 MHz RF contribution from ACAS to ensure that the SSR frequency band does not become congested. The current situation is ACAS II as recently modified to ACAS V7.1 through European Commission legislation detailed in Ref Doc 7 however whilst this improves the algorithms employed in the system improvements to the spectrum efficiency of the system will be achieved through the introduction of ACAS Hybrid Surveillance (See section 3.1.1.3).

3.1.1.1 Migration of Responsibility and Functionali ty from Ground to Air The most significant difference between the surveillance infrastructure of the recent past and that which will be established to support long term future applications is a migration in functionality from ground based sensors to a comprehensive suite of avionics supporting a range of demanding surveillance applications. The position and other airborne parameters will be provided by the airborne part of the surveillance system (ADS-B Out) and will also be directly used by other aircraft (ADS-B In) to support new surveillance applications. The migration of functionality paves the way towards a migration of responsibility in which the air-crew is increasingly aware of the traffic situation and could take responsibility for the separation of their aircraft from others.

Airborne surveillance applications represent an important change in perspective from current ATC practices.

To enable this evolution and migration of functionality a corresponding development in the support infrastructure is necessary. The resolving of design anomalies within a transponder or related avionics component installed on hundreds or even thousands of aircraft will be more difficult and time consuming to achieve than resolving similar issues on a more limited number of ground-stations. To mitigate this, the shift of functionality must therefore also be accompanied by a corresponding shift in responsibility and activity by all partners involved in surveillance. More demanding standardisation, certification methodologies and regulation will help address the issue in its early stages however


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provision, possibly including additional legislative mechanisms, must be foreseen to address anomalies that are identified when in operational service.

Activities to record and analyse the performance of avionics and transponders will be required.

3.1.1.2 Increasing choice of Surveillance Technique s A less apparent but equally significant difference stems from the availability of a broader range of surveillance techniques available to Air Navigation Service Providers.

ANSPs providing separation services will need to make decisions regarding which technique best matches the specific needs of their local environment, their terrain and a host of other characteristics.

In general the expected trend will be to achieve the required levels of continuity of service by retaining an independent cooperative layer together with the new dependent cooperative surveillance provided by ADS-B. However in this case 100% equipage of ADS-B is required – at least in airspace where ADS-B applications will contribute to the surveillance service and enabled by airspace segregation and mandates.

Combinations of independent and dependent cooperative surveillance means are expected to bring benefits in terms of cost and performance. For example composite ADS-B / WAM systems are widely offered by industry and are being deployed by ANSPs in Europe and worldwide. The use of multiple systems each providing surveillance data provides data integrity and duplicated coverage but reinforces the requirement for appropriate data fusion systems.

3.1.1.3 Adaptations to the use of the RF Spectrum

3.1.1.3.1 Spectrum Overview Until 2030 ATC surveillance in Europe will rely on 3 families of surveillance technology

• Independent cooperative surveillance (using 1030/1090 MHz) • Dependent cooperative surveillance (using 1090 MHz) • Independent non-cooperative surveillance (Using spectrum allocated within L Band and S

Band)

In addition the 1030/1090 MHz SSR bands also support the safe operation of airborne safety nets (i.e. ACAS) and of forthcoming air to air applications (e.g. in-trail procedure) and are needed to support the deployment of cooperative surface surveillance systems at airports. It is also to be noted that the operation of ACAS (airborne safety net) also relies upon the use of the 1030/1090 MHz SSR bands.

ADS-B operations rely on GNSS and the RF bands in which it operates (dependent upon which GNSS technology is used on board the aircraft. Options could include GPS, GLONASS, Galileo or COMPASS-Beidou).

Non-cooperative surveillance technology will continue to deployed where operationally needed to address safety and/or security requirements and will make use of the L band (long range PSR for En Route airspace although their use is expected to decline) and of the S Band (medium range PSR for TMA airspace and military long range PSR). It is understood that some States are considering the introduction of spectrum charging initiatives and these may place significant additional financial costs or constraints in providing surveillance services.

Depending on the future development and deployment of multi-static PSR technology to replace classical mono-static PSR technology, it could be envisaged that some portions of the L-Band and of the S-Band could be released as the MSPSR is expected to utilise a more narrow effective band-width (in the L-band) than classical PSR. MSPSR frequency requirements could be very efficient if a coordinated management scheme for frequency allocation is employed.

The Commission Implementing Regulation (EU) No 1207/2011 laying down requirements for the performance and the interoperability of surveillance for the single European sky (Ref Doc 4) has a dedicated Article (Article 6 Spectrum protection) related to spectrum. This requires member states to make efficient use of the 1030/1090 MHz SSR bands by prohibiting excessive interrogations from ground systems.


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As a summary, until 2030 ATC (air) surveillance will make use of the following RF spectrum bands:

• 1030/1090 MHz SSR bands (for Mode A/C SSR, Mode S SSR, Multi-lateration systems and ADS-B Extended squitter in and out).

• Portions of L band allocated to GNSS systems. • 1215 to 1400 MHz band (classical PSR and MSPSR) • 2700 to 3400 MHz band (classical PSR) • 15.4 to 15.7 GHz and 9 GHz band for SMR

This roadmap assumes that appropriate measures are taken to ensure that the required spectrum is available and protected against interferences from other systems to ensure the safe operation of surveillance ATC. (See SESAR 15.1.6 deliverable Ref Docs 11).

3.1.1.3.2 Better In-band spectrum management A common attribute that all the new surveillance techniques offer is the potential for achieving improved spectrum efficiency.

Rationalisation of the co-operative surveillance infrastructure in areas of high RF density is necessary. Such measures may include the removal of spectrally inefficient Mode A/C type systems, deployment of modern sensors, increased sharing of data between surveillance service providers (civil/civil and civil/military), integration of Mode S ground-stations into a single cluster and improved management of Mode S interrogators.

By deploying spectrum efficient co-operative surveillance systems the cost and the need for a second data link to support 1030 / 1090 MHz type operations will be obviated. This is desirable as the introduction of a second data link to support ADS-B applications would be an expensive and complex undertaking. Its introduction would, furthermore, also introduce potential safety issues that are not present on a single link solution.

It is therefore considered to be preferable to use the existing 10390/1090 MHz band but to do so requires improvements to the management and use of the band. Topics for consideration include:

• The development of Hybrid ACAS (also known as Hybrid Surveillance), or ‘Improved Hybrid ACAS’ offers, by using ADS-B information to reduce the usage of 1030/1090 MHz spectrum by ACAS, major savings in RF usage of the 1090MHz band. This development alone could make a significant improvement in spectrum occupancy and should therefore be considered as a subject for further development.

• Reductions in Mode S All Call transmissions enabled through passive acquisition of the aircraft through the use of its ADS-B.

• Integrating Mode S ground-stations into single clusters thereby achieving efficiencies not only in terms of RF usage but also with regard to Mode S interrogator codes.

• Rationalisation of the 1030/1090 MHz usage through the sharing of common assets/surveillance data and the deployment of more spectrally efficient surveillance means to replace existing SSR Mode A/C sensors.

Thus this roadmap does not foresee the use of links other than 1090 MHz for Surveillance applications.

Rationalisation of the PSR infrastructure and/or inclusion of MSPSR will address PSR spectrum efficiencies.

3.1.1.3.3 Management of 1030/1090 MHz Link Usage The global use of the RF bands identified above allows a cost effective interoperable system. These bands are shared by different applications including military applications. Optimising the use of 1030/1090 MHz is therefore of the first importance.

Significant improvement of 1030/1090 MHz is achievable through the replacement, where appropriate, of radar by ADS-B and passive WAM (or WAM configurations with reduced ‘RF footprint’), the removal of the old SSR Mode A/C systems (both sliding window and mono-pulse SSR) and through SSR Mode S radar clustering and surveillance data sharing.


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ACAS is a major contributor to the 1030/1090 RF band usage. Its impact needs to be reduced and this can be achieved for example through requirements to use the ACAS Hybrid4 surveillance technique. The reduction of spectrum utilisation by ACAS through the widespread deployment of ACAS Hybrid surveillance could, according to initial investigations performed within the context of RTCA 147 (for an American environment – and still requiring further analysis for potential impact within a European context), achieve a reduction of up 80% of the ACAS contribution to the RF environment. As the ACAS RF contribution can account for more than 50% of signals in some dense regions of airspace a reduction in this figure could be beneficial to the performance of surveillance systems that also use the 1030/1090 MHz frequency band.

In addition an increase of the 1090 MHz ES data capacity is being prepared by ICAO. This is to be achieved by adding phase modulations on the same SSR signals. This opens the possibility for a significant increase in the data throughput on the 1090 MHz RF band whilst retaining full compatibility in a mixed environment. Systems, such as the ground based ADS-B stations, will however need to be adapted to receive and process the additional information that is contained in the modulation component of the signal.

3.1.1.3.4 Spectrum Charging and its impact on PSR The frequency spectrum allocated to non-cooperative surveillance is under pressure as Non-ATM services are encroaching upon the bands and spectrum charging or similar schemes are also under consideration. Spectrum charging may promote more stringent in band spectrum management of the PSR in the L and S bands and thus permit the release of some portions of these bands for other purposes.

Whilst spectrum charging, the mandatory carriage of transponders and a need for cost efficiencies will drive a reduction in the use of conventional PSR it is anticipated that some form of non-cooperative surveillance technique will be retained where deemed to be operationally necessary to mitigate against avionic failures and support the identification of the presence of aircraft intruding, accidentally or deliberately, into controlled airspace.

Whether or not charging schemes are applied to such applications will have to be decided at national political level.

MSPSR is likely, subject to successful development and validation, to offer significant savings in terms of spectrum utilisation.

Whilst outside the scope of a paper regarding ATC it is noted that to ensure national security Air Defence PSR will continue to be used in the near and mid term future.

3.1.1.4 Change to the operational environment

3.1.1.4.1 Generic Changes to the Operational Enviro nment The operational environment is in a period of significant change. Many of these changes have the potential to introduce significant changes to the manner in which surveillance services are provided.

Key changes include the following:

• The recent publication of a range of European Commission Implementing Regulations introduces new rules upon numerous stakeholders with an interest in surveillance. These represent a major advance in consistent application of mandatory requirements throughout European airspace.

• There may also be a need for the requirements of the Implementing Regulations to be supplemented by local initiatives in the short term and probably European wide initiatives in the longer term e.g. to extend coverage of ADS-B to all aircraft.

• Legally binding requirements are being placed upon ANSPs. Surveillance is one area with the potential to offer solutions to meeting these targets.

• The number of flights conducted in European airspace will increase but the increase is not predicted to be uniform. Growth in Eastern Europe will be the strongest.

• Resolving congestion at airports may introduce requirements for additional surveillance sensors – where possible these should be configured as gap fillers with supporting data

4 ACAS Hybrid Surveillance uses the ADS-B (1090 MHz) information transmitted from neighboring aircraft to support a reduction in the number of active interrogations that the ACAS system makes.


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obtained through sharing of information available from other sensors to minimimse the impact of introducing further demands upon the RF environment and an aircrafts avionics.

• Low cost airlines are increasingly using secondary and tertiary airports and this may require the introduction of additional surveillance capabilities,

• The composition of the fleet of aircraft operating in European airspace is changing. The features of VLJs and super-heavy jets need to be considered to ensure that the surveillance infrastructure is capable of safe, efficient and timely detection of such platforms. The potential impact of the introduction of Remotely Piloted Aircraft is detailed further in the following section.

3.1.1.4.2 Change to the Operational Environment due to the Introduction of Remotely Piloted Aircraft (RPA)

The introduction of Remotely Piloted Aircraft (RPA) into operations in controlled airspace is expected to happen in Phase 2 of this roadmap. There are significant issues to be considered regarding the deployment of RPAs from a surveillance perspective.

They will need to be addressed to ensure that RPA can be operated safely in controlled and non-controlled airspace. (See SESAR Work-packages 9 and 15)

3.1.1.4.3 Increasing use of Downlinked Airborne Par ameters Modern surveillance systems (and the tools they support) provide benefits in terms of safety through the use of airborne information automatically downlinked by surveillance systems. (See section 2.1.4).

The current trend is to make more use of the short term intent information (which are already made available via ADS-B Extended Squitter transmissions and with Mode S systems for enhanced surveillance). However future operational improvements are expected to impose requirements for the transmission of longer term intent information. Avionics architecture should therefore be designed to provide such information to the surveillance system.

Whilst the population of air traffic is foreseen to increase across Europe the separation minima, currently typically either 3 NM or 5 NM, is anticipated to remain the same within most European TMA and En-Route airspace. The surveillance techniques available within the course of the next 20 years are capable of meeting such performance demands and, where deemed operationally necessary by ANSPs, a reduction in separation minima could also be accommodated with surveillance techniques such as WAM and ADS-B providing a key resource in addressing more demanding performance requirements.

3.2 Phase 1 of the Roadmap - Today to 2020 The European surveillance infrastructure is already well developed. The surveillance techniques established over recent years support the foundations for the SESAR ATM Masterplan and the technical requirements to achieve those foreseen operational requirements.

The infrastructure must however adapt to meet the changing environment. Local implementations will be tailored to meet local demands by exploiting recent technological developments and using the most appropriate features from an increasing number of surveillance techniques.

A significant change is that in the very near future even more of the avionics carried on board certain civil and military/State aircraft will become integrated into the surveillance infrastructure and will be used to support the provision of airborne information. Civil and Military surveillance systems will thus have to take into account and be assessed together with an increasingly diverse range of avionic components – such as positioning systems, traffic computers and cockpit display systems, as well as the transponders.

Whilst under specific conditions, transport type State aircraft will be mandated for Mode S EHS and ADS-B equipage they may be exempted against these requirements for a further period of time after December 2017 it is to be noted that non-ADS-B equipped State aircraft may not be permitted to fly in volumes of airspace designated as requiring ADS-B equipage in cases where ANSPs prove that those aircraft could not be handled within the safety limits of the ANSPs Air Traffic Management System. Details are specified in the European Commission Implementing Regulation No 1207/2011 (Ref Doc 5).


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Cost pressures and the ageing of existing inefficient surveillance sensors will lead to a more efficient infrastructure – efficiency offered in terms of spectrum but also, through for example the provision of Aircraft Derived Data items, in supporting ATC controller efficiencies. It is foreseen that there will be an increase in the sharing of surveillance data within FABS, between civil and military ANSPs and across national borders.

3.2.1 Description of the Phase 1 Surveillance Infrastruct ure In summary the surveillance architecture of Phase 1 appears as follows:

• Until 2020 the majority of aeronautical surveillance will continue to be based on independent cooperative surveillance systems using 1030/1090MHz RF bands (SSR, SSR Mode S, WAM and ADS-B) complemented, where required, by non-cooperative systems (PSR).

• Similarly multilateration systems will be configured to provide ATC with detailed knowledge of the location and identify of aircraft and vehicles on the airport surface. This can be complemented by SMR where operationally necessary.

• ADS-C will continue to be used to support ATC operations in oceanic areas. ADS-B In operations may start to replace the use of ADS-C.

• Widespread deployment of ADS-B avionics in accordance with the requirements of European Commission Implementing Regulation No 1207/2011 (Ref Doc 5) will be achieved by 2018.

Further details are provided in the following sections.

3.2.1.1 Independent Cooperative Surveillance Mode S Elementary Surveillance (ELS) (use of Aircraft Identification in place of Mode A code) and Mode S Enhanced Surveillance (EHS) (use of other airborne parameters) are already deployed and will continue to provide surveillance across most European high density airspace. This is being extended to the complete airspace of Europe (European Union countries plus some adjacent countries) through the introduction of legislation published by the European Commission (Regulation 1207/2011). (Ref Doc 5) Aircraft identification is being rolled out and will be used in all Europe as the main means of identification by 2020.

Taking into account the European Commission (Regulation 1206/2011) (the ACID IR) (Ref Doc 6) it is expected that by January 2020 a large number of existing civil conventional SSR (Mode A/C) will be decommissioned and that a large number military conventional SSR used for ATC will be decommissioned by January 2025.

Obsolescence of Mode A/C type radars and their replacement by either Mode S or WAM systems or ADS-B will further cleanse the 1030/1090 MHz RF spectrum. Increased clustering of Mode S ground stations would also help alleviate RF congestion.

In the latter years of Phase 1 the Mode S infrastructure that was deployed in around 2000 will be nearing the end of its operational life. In some cases mid-life upgrades but in others replacement by WAM (with ADS-B provision pending aircraft equipage for full ADS-B operational use).

Rationalisation of the surveillance infrastructure in areas of high RF density is necessary.

In the latter years of Phase 1 it is anticipated that all aircraft, including non-powered VFR, RPA and military, will be equipped with cooperative surveillance avionics. Some platforms are unlikely to be required to meet the same demanding performance specifications as those foreseen for commercial aircraft. The operational requirements, specifications and means of certification of these reduced capability systems are to be further developed for the various types of airspace users.

3.2.1.2 Dependent Cooperative Surveillance

3.2.1.2.1 ADS-B Out used in Non-Radar Airspace The transmission of ADS-B information (ADS-B Out) is already used for surveillance in some non radar areas (NRA) of the world and is likely to be used operationally in some European NRA airspace in 2012. This initial usage may be dependent upon the use of lists of aircraft known to be appropriately configured. This information would be used within the surveillance system to filter eligible aircraft from non-certified ADS-B platforms. Changes to the flight plan designators for ADS-B may also be required to support ATC in identifying aircraft with appropriately configured ADS-B data sources.


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3.2.1.2.2 ADS-B Out used in Radar Airspace Through the deployment of dedicated ADS-B ground-stations or through ADS-B hardware configured within WAM ground-stations ADS-B ground-station functionality is already becoming increasingly established across much of Europe.

Further hardware will continue to be deployed to allow ANSPs to establish familiarity and confidence in the technique leading to operational use. The deployment of ADS-B ground-stations will be phased to prevent ANSPs incurring unnecessary costs of duplicated surveillance systems. However once currently deployed SSR based systems reach an age at which they are becoming costly to maintain and service then the deployment rate of ADS-B and WAM ground-stations will accelerate.

It is recognised that to support detection in a radar environment (ADS-B RAD application) requires either segregation of airspace or total equipage of aircraft in the volume of airspace under ADS-B control. Thus, prior to establishing ADS-B RAD operational services, the European Commission legislation will be supplemented by the introduction of local mandates giving advance notification of ADS-B requirements to operators of aircraft that are below the thresholds defined in the European Commission regulation.

ADS-B in European airspace will predominantly use 1090MHz therefore there is no need for ADS-R (ADS-B Rebroadcast) functionality. (It is foreseen that the use of ADS-B using VDL Mode 4 techniques will be phased out within Phase 1 of this roadmap).

Although ADS-B dependent surveillance may initially be used to provide localised pockets surveillance coverage, in general, it will, towards the end of the Phase 1 timescale, be used to replace a layer of independent cooperative surveillance. An independent cooperative surveillance layer provided either by Mode S radar or by Wide Area Multilateration systems will remain to ensure the necessary continuity of service and safety mitigations.

Whilst the requirement to configure ADS-B avionics on aircraft below the weight and speed thresholds defined in European Commission Implementing Regulation No 1207/2011 will initially have been limited to small pockets of airspace where ADS-B applications were being performed it is likely that the widespread deployment of ADS-B will require a more harmonised approach requiring ADS-B Out functionality deployed on ALL aircraft. (See section 4.1.5)

The use of ADS-B data will also support a range of supplementary benefits in addition to operational ATC. The use of high quality data provided by appropriately configured ADS-B platforms can used to refine system tracker settings which in turn will improve system performance upon non-ADS-B equipped traffic.

Similarly Mode S EHS parameters are not provided from all aircraft due to restrictions within their avionic architecture. Nevertheless the data that is made available provides ATC with safety and work-load benefits. In a similar manner ADS-B could be used to provide ADDs even if initially only a sub-set of aircraft in the airspace are appropriately equipped. Similarly as ADS-B Out version 2 also provides ACAS RA DOWNLINK messages the information could be used in support of monitoring activities.

3.2.1.2.3 ADS-B In The availability of ADS-B Out will enable, in the early stages of Phase 1, the introduction of new air-air surveillance applications, made possible for aircraft voluntarily equipped with ADS-B In.

Air Traffic Situation Awareness (ATSAW) facilitated by ADS-B In provides pilots with a real-time picture of the surrounding traffic during all phases of flight. It gives pilots the ability to move more frequently to a more efficient altitude when operating outside ground surveillance coverage. ATSAW also supports visual separation on approach and provides traffic situational awareness on the airport surface.

Initial ADS-B In applications can be performed by aircraft equipped with avionics meeting ED-102 however the more demanding ADS-B applications such as Interval Management, Surface and Indicators and Alerts will require compliance with the avionic requirements detailed in European Commission Implementing Regulation No 1207/2011. (Ref Doc 5).


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3.2.1.3 Independent Non-Cooperative Surveillance Cooperative surveillance systems will provide the main source of surveillance data. It will be supported by independent non-cooperative surveillance (primary radar or successor when available) where necessary, i.e., where the risk of intrusion of non-equipped aircraft is too high. The need for non-cooperative surveillance might be reduced by mandating the carriage of cooperative surveillance system in a wider area. However, to ensure national security the need to continue operation of Air Defence PSR will continue.

MSPSR will be developed and deployed where benefits over conventional PSR can be demonstrated. It is anticipated that, depending upon operational requirements, they will be deployed principally in an active configuration but perhaps not exclusively.

The continuing provision of PSR coverage in the En-Route airspace of some States will be reassessed based upon cost and operational need. It may be decided that the use of PSR data for aircraft above 20 000 ft is a rare occurrence and is not strictly necessary. It may be that even if Passive MSPSR / PCL, have limited vertical coverage capabilities, their performance may be sufficient to meet the majority of operational demands.

It could be envisaged that Military ANSPs could provide non-cooperative data whilst their civilian counterpart provides cooperative data.

3.2.2 Surveillance Coverage Within Phase 1 of this surveillance roadmap it is anticipated that SSR Mode A/C radars will be phased out. Where surveillance coverage cannot be provided by other surveillance sensors a new sensor will be deployed. It is anticipated that WAM systems, with ADS-B functionality included but not operationally exploited – at least in the early stages, will be deployed in the majority of cases.

The vision for ground surveillance in en-route and terminal areas remains at least 2 parallel layers of cooperative surveillance providing the necessary levels of continuity of service. Towards the end of Phase 1 ADS-B RAD type applications will form a ‘stand-alone’ layer of surveillance. The use of this layer would be combined with a layer of independent surveillance, the latter provided by Mode S or Wide Area Multilateration. Where there is a need for Primary Surveillance Radars to address safety concerns, it would initially be met by conventional PSRs although once developed and validated it could also be fulfilled by the spectrum efficient Multi-static PSR (MSPSR).

The deployment of new sensors/surveillance technologies will be dependent upon the age of the current infrastructure and the ANSPs desire to achieve maximum utilisation from existing resources before deploying new systems.

Thus the evolution of the surveillance infrastructure will be driven not only by the operational requirements but also the availability of new techniques and systems, such as Wide Area Multilateration and in regions with appropriate equipage levels, Automatic Dependent Surveillance -Broadcast (ADS-B) etc. which will enable rationalisation of the ground infrastructure and development of new applications such as airborne surveillance.

3.3 Phase 2 of the Roadmap - 2020 to 2030 In the later years of Phase 1 and the early years of Phase 2 the European surveillance infrastructure will undergo a significant step forward in its evolution. The infrastructure will be adapted to exploit fully the availability of cost-efficient yet high performance surveillance techniques such as ADS-B and to meet the changing environment. Local implementations will be tailored to meet local demands by exploiting recent technological developments and using the most appropriate features from an increasing number of surveillance techniques – which may include Satellite ADS-B.

Cost pressures and the ageing of existing inefficient surveillance sensors during Phase 1 will have lead to a more efficient infrastructure – efficiency offered in terms of spectrum but also in supporting ATC controller efficiencies. It is foreseen that throughout the duration of the roadmap there will be an increase in the sharing of surveillance data within FABS, between civil and military ANSPs and across national borders.

Whilst refinements to capabilities may be identified in the course of the development of the Operational Improvements it is anticipated that the surveillance infrastructure currently foreseen could meet all the demands placed upon it. However, the timely provision of changes, including any mandatory requirements that may impact upon surveillance related avionics, should be carefully


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managed to minimise the burden on aircraft operators and maintain interoperability with military and state authorities.

3.3.1 Description of the Phase 2 Surveillance Infrastruct ure In summary the surveillance architecture of Phase 2 appears as follows:

• Until 2030 the majority of aeronautical surveillance will continue to be based on cooperative surveillance systems using 1030/1090MHz RF bands. The surveillance information presented to ATC will comprise of data obtained/shared with other ANSPs and data obtained locally from a surveillance infrastructure exploiting the benefits of the numerous available surveillance techniques. Where deemed necessary to address local safety or security concerns independent non-cooperative systems, PSR and/or MSPSR, in either active and/or passive form, would be deployed.

• A portfolio of ADS-B In applications will be in operational use. Some of the applications currently foreseen require further development prior to operational deployment.

• The use of ADS-C in support of ATC operations in oceanic areas could be influenced by ADS-B In and/or, subject to development, validation and an appropriate business case, Satellite ADS-B.

• Deployment of ACAS Hybrid Surveillance supports continuing improvements to 1030/1090 occupancy and contributes to a reduction in the need for a second/alternative data link for ADS-B.

• Numerous SESAR Operational Improvements have identified a potential need for further downlinked aircraft parameters. To facilitate these OIs some form of improved 1090 MHz modulation schemes should be established to prevent undue pressure on the frequency band. These spectrum improvements will free up capacity for additional ADDs to be broadcast e.g. wake vortex, comms frequencies etc. It is to be noted however that in addition to avionic changes that ground station improvements will be required to receive the data that is broadcast using new modulation mechanisms.

Further details are provided in the following sections.

3.3.1.1 Independent Cooperative Surveillance Mode S Elementary Surveillance (ELS) and Mode S Enhanced Surveillance (EHS) will continue to provide surveillance across most European high density airspace. Mode S systems that were deployed in the early stages of Phase 1 will have reached the end of their operational life and, where appropriate, will be replaced by composite ADS-B and WAM ground-stations.

The peak of RF congestion – an increasing number of aircraft flying prior to the introduction of rationalisation methods and ACAS spectrum efficiencies, will have passed.

3.3.1.2 Dependent Cooperative Surveillance During Phase 2 ADS-B surveillance data will become established as the principal data source in some areas. Not only will ADS-B Out functionality be widely deployed but ADS-B In will be in increasing use and supporting a range of demanding surveillance applications.

The initial use of ADS-B In is foreseen to be undertaken on a voluntary basis however it may become necessary to introduce mandatory requirements for its deployment in certain volumes of airspace where system-wide benefits could be obtained from widespread deployment.

Whilst the requirement to configure ADS-B avionics on aircraft below the weight and speed thresholds defined in European Commission Implementing Regulation No 1207/2011 will initially have been limited to small pockets of airspace where ADS-B applications were being performed it is likely that the widespread deployment of ADS-B will require a more harmonised approach requiring ADS-B Out functionality deployed on ALL aircraft. (See section 4.1.5)

An independent cooperative surveillance layer provided either by Mode S radar or by Wide Area Multilateration systems is expected to remain alongside an ADS-B infrastructure to provide the necessary levels of continuity of service and safety case mitigation.


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3.3.1.3 Independent Non-Cooperative Surveillance Cooperative surveillance will provide the main source of surveillance information. It will be supported by independent non-cooperative surveillance (primary surveillance radar or successor when available) where necessary, i.e., where the risk of intrusion of non-equipped aircraft is high. The need for non-cooperative surveillance is expected to have been reduced by the mandatory carriage of cooperative surveillance system across Europe.

MSPSR will be developed and deployed providing operational support – principally in an active configuration but perhaps not exclusively – depending upon operational requirements.

Primary Surveillance Radars are current used to support En-Route operations in a limited number of States. It is anticipated, based upon current trends and cost-pressures that the use of non-cooperative surveillance coverage in the En-Route airspace will reduce further. In this occurrence it could be envisaged that Military ANSPs could provide independent non-cooperative data whilst their civilian counterpart provides cooperative data.

3.3.1.4 Integration of Remotely Piloted Aircraft (R PA) into the Surveillance Infrastructure

During Phase2 it is foreseen that the number of RPA flying within European airspace will increase. Their use must be integrated into the ATM system with surveillance being the initial interface.

Integration issues such as those described in section 2.1.5.2.2 will need to be addressed.

3.3.2 Surveillance Coverage During Phase 2 of this surveillance roadmap ADS-B surveillance data will become established as the principal data source in some areas. Within Phase 2 it is anticipated that SSR Mode S radars will be remain where technically, financially and operationally appropriate. A key consideration that ANSPs will make prior to replacing an ageing sensor is that a new sensor will be deployed only where surveillance coverage cannot be provided by other already-deployed surveillance sensors.

The data circulating in the European surveillance Infrastructure will be fused. The source of the surveillance data, be it SSR, ADS-B, WAM etc, will, in an increasing number of cases, be transparent to the controller. Information shall only be presented to them if it is ‘fit for purpose’. This will include ADDs where available.

Sharing of data will support rationalisation of infrastructure and a sharing of cost burdens. It is anticipated that this will continue and extend between ANSPs and their military / State counterparts.


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3.4 Roadmap in Graphical Form The following figures show the expected evolution of surveillance techniques over the next 20 years for each of the main areas of surveillance service. Solid bars represent the operational availability of techniques. Arrows represent either a phasing in or out of that technique.

3.4.1 Airborne surveillance by ground

Surveillance Technique

Near Term

Long Term (+- 2030)

Comments

Independent non-

cooperative

Independent Non Cooperative systems (i.e. PSR and/or MSPSR) deployed if necessary.

MSPSR deployed to address spectrum charges and a more demanding operational environment (Subject to development).

Mode A/C sensors phased out due to RF inefficiencies, the availability of cost effective alternatives and also by an increasing dependency upon the use of ACID (ELS) and airborne parameters (EHS).

Higher traffic density / ELS / EHS More spectrally efficient than Mode A/C

Independent cooperative

Depending upon complexity of network, potential for cost effective surveillance in certain terrain and can support a reduction of spectrum usage.

In Non Radar Environment

In Radar Environment as one layer of surveillance cover.

Depending upon complexity of network, potential for cost effective means to support more demanding future applications. Ground stations may be combined with WAM and in the longer term possibly even MSPSR.

Dependent cooperative

In remote areas ADS-C (Surveillance) might be phased out depending on the feasibility of satellite ADS-B and the use of ADS-B In applications.

Figure 3: Airborne surveillance by ground

MSPSR

PSR

SSR

Mode S SSR

Remains in regions of high traffic density

ADS-C

ADS-B Sat

WAM

ADS-B

ADS-B In Applications


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3.4.2 Aircraft-Aircraft Surveillance

Surveillance Application

Near Term Long Term (+- 2030)

comments

Use Mode S and Mode A/C interrogations.

ACAS

High reduction of RF contribution achieved through improvements to the ACAS system.

Improved knowledge of relative aircraft position.

Aircraft Applications

AIRB1 VSA2

ITP3

SURF4

IM5

SURF-IA and Airborne Separation

Airborne self separation

Requires ADS-OUT and also ADS-B IN (which will initially be under voluntary equipage).

Future SESAR applications may place more demanding requirements on ADS-B necessitating design changes and cockpit system upgrades.

Figure 4: Aircraft to Aircraft Surveillance

1 AIRB: Enhanced Traffic Situational Awareness during Flight Operations 2 VSA: Enhanced Visual Separation on Approach 3 ITP. In-trail-procedure 4 SURF: Enhanced traffic situational awareness on the airport surface (includes aircraft to vehicles) 5 IM. Interval Management 6 IA: Indicators and Alerts

SSR

Hybrid Surveillance

ADS-B In

ACAS II v7.1


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4 Summary of Tasks Identified as Necessary to Suppo rt the Transition to the Target State

It is recognised that achieving this enhanced surveillance infrastructure will require significant effort, resources and commitment. The transition to the future will be challenging. Such challenges can only be addressed by all parties working in concert.

The following topics are proposed for consideration / inclusion within the next release of the ATM Masterplan document or within similar supporting documentation.

It should be noted that some of the tasks identifie d below are likely to be conducted anyway by ICAO or RTCA or, subject to verification, would be part of the remit of a European Network Manager.

4.1 Identified Work Areas The following sections identify activities that need to be conducted to ensure that the necessary technologies or support infrastructure are available to support surveillance in 2030. In some cases the body responsible is identified however this is not established for all activities.

4.1.1 Support the Development of ADS-B In Applications Whilst standards for initial ATSAW applications are readily available and operations have already started there are more demanding spacing applications that are currently being standardised. SESAR Work Packages such as 5.6.6 (ASAS Sequencing and Merging – ASAS IM) are addressing interval management, crossing and passing, separation and self-separation applications.

Developing these applications to the point of operational readiness will be a significant task. It may become necessary to adapt the existing avionics standards and configurations to meet the requirements placed upon ADS-B avionics as a result of such developments.

4.1.2 Support the Provision of Additional ADDs from an Ai rcraft: It is important to note in the context of the ATM Masterplan and similar initiatives such as ICAO GANIS, that aircraft operator representatives are likely to be reticent to add new ADDs (i.e. those not already included in CS-ACNS) in the near future.

The relatively recent upgrade to Mode S EHS and the on-going upgrade to ADS-B by 2018 have imposed cost burdens upon the aircraft operators. Consequently any dates proposed in the SESAR ATM Masterplan should be considered in this context. New ADDs broadcast over 1090MHz should not be identified as necessary before approximately 20225.

4.1.3 1030/1090 Spectrum Activities

4.1.3.1 Undertake 1030/1090 MHz Spectrum Management Improvements It is necessary to establish and verify the efficacy of measures such as those outlined below to ensure that those OIs dependent upon surveillance or that may require additional ADDs to support future applications (e.g. 4D trajectories) can continue to be achieved. Activities supporting improvements to the 1030/1090 MHz include:

• ACAS Hybrid Surveillance (ACAS and ADS-B combined, also with a reduction in ACAS transmission rates) (See SESAR WP 9.47)

o RTCA have already produced Minimum Operational Performance Standards (MOPS) for Traffic Alert and Collision Avoidance System II (TCAS II) Hybrid Surveillance DO-300 (Ref doc 26) however further refinements are currently under discussion.

o This technique is foreseen to achieve a reduction of 80% of the ACAS contribution to the RF environment. The ACAS contribution can account for more than 50% of

5 This date is proposed as it allows 1 year before drafting activities commence of a new IR, it allows 3 years for the writing and consultation before it is published and then 6 years for a phased introduction (i.e. approx 2022). A period of time will then be required to ensure that all configurations are correct.


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signals in dense traffic airspace. Thus, the use of this technique alone will bring significant benefits.

o Legislation mandating the equipage of such systems may be necessary – draft text to indicate need for possible mandates is included in the draft Legislative Roadmap.

• Other means for spectrum improvements include: o Rationalisation of the surveillance infrastructure:

� Removal of older Mode A/C SSRs, � Deployment of Mode S/WAM/ADS-B, � Clustering of Mode S groundstations � Passive acquisition of targets by Mode S and WAM through the use of the

targets ADS-B transmissions. � Increased sharing of surveillance data.

o Improved Mode S interrogator management. o Improved frequency management including:

� Monitoring of RF hot spots, � Reduction of Transmission powers and PRF rates

• provision is included within the European Commission Implementing regulation No 1207/2011 (Ref Doc 5)

� Licensing of Mode A/C transmitters and a drive for their removal in Core Europe,

4.1.3.2 Develop Measures to Support Increased Throu ghput of ADDs The RF congestion caused by broadcasting even more information over the 1090MHz frequency band e.g. additional ADDs such as those supporting 4D trajectories, could be mitigated against by developing improved transponder transmission modulation techniques which would allow more data to be transmitted within that band. (An example is already patented (by ACSS) and it is understood that IPR issues that were threatening to delay its use have been resolved. Further mechanisms could be addressed under SESAR R&D).

The use of this technique will however necessitate changes to both the avionics (transponder) and to the Mode S EHS, ADS-B and WAM ground-stations receiving the information contained in the phase modulation element of the signal. As this technique is backwardly compatible only those aircraft and ground-stations wishing to benefit from the additional data need to be upgraded. Consequently it is expected that this technique will be rolled out in a phased manner – initially focussed upon specific volumes of airspace and the aircraft that operate within it – subject to local legislation. (The design of Satellite ADS-B systems, see 4.1.4, should also consider whether the phase modulated signals are to be processed and the data relayed to the ground).

Once the increased capacity is validated and in operational use the technique may prove to be a catalyst for the broadcast of a greater diversity of ADDs.

Additional ADDs, such as wake vortex, are already foreseen but there may be some extras that could be beneficial in ways not yet considered. The transmission of the VHF voice comms frequency as a downlinked parameter could be considered.

4.1.4 Investigate and Develop Means to Provide Oceanic or Remote Region Surveillance

Satellite ADS-B surveillance systems, such as the Iridium system that is currently being assessed by the FAA and others, could be a means to provide surveillance cover in oceanic or low density regions. In section 2.3.3.3 it is proposed that it should be mentioned in the SESAR ATM Masterplan i.e. to assess viability, operational need (if any) and business case for inclusion in the surveillance roadmap.

The initial Iridium timescales are probably too demanding for much from a SESAR technical perspective, apart from monitoring progress however a more general assessment of the potential benefits should be performed.

It is anticipated that in the longer term technical improvements to the satellite receiver capabilities could allow such an approach to be used in airspace with denser traffic densities. An assessment of the technical specifications for this could be considered for inclusion within the scope of work supporting the SESAR ATM Masterplan activities.


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4.1.5 Enable ADS-B Equipage on ALL Aircraft 100% of the aircraft flying in airspace in which ADS-B is used to provide a separation service need to be appropriately equipped.

Whilst the requirement to configure ADS-B avionics on aircraft below the weight and speed thresholds defined in European Commission Implementing Regulation No 1207/2011 will initially have been limited to small pockets of airspace where ADS-B applications were being performed it is likely that the widespread deployment of ADS-B will require a more harmonised approach requiring ADS-B Out functionality deployed on ALL aircraft. A target date of early Phase 2 is proposed.

ADS-B Equipage on ALL Aircraft would also contribute to safety through increased situational awareness of small aircraft. Such deployment is dependent upon legislation and the timely availability of affordable avionic components.

Additional legislation for all aircraft to be ADS-B equipped may be achieved via European wide legislation. Draft text to indicate need for possible mandates is included in the Legislative Roadmap.

The impact of equipping ALL flying things with an ADS-B set of avionics needs to be assessed in line with developing specifications for lower power/lower functionality avionics. Additionally the operational requirements need to be detailed. It may be operationally acceptable to have lower performance capabilities or lower power transmissions at a lower squitter rate (to conserve battery power). Thus, developing, validating and certifying an appropriate suite of avionics is identified as a task to be undertaken.

4.1.6 Maintain the Surveillance Infrastructure There are activities which need to be performed to ensure that the surveillance infrastructure is maintained in a ‘healthy state’ from a wider system perspective. There are a number of ways in which the performance of the Surveillance System can be compromised. These include:

• Transponder / Avionic failures (where a hardware fault has developed due to component failure).

• Transponder / Avionic configuration design error (i.e. transponder design error whereby all transponders of that version exhibit the same erroneous characteristics).

• System design error (where the design specification for the integrated surveillance system does not permit the system to achieve full operational performance due to characteristics that were not taken into account in the system design).

• Ground station hardware failure (where a hardware fault has developed due to component failure).

Whilst the resolution of ground station hardware failures is the responsibility of the ANSP’s, the resolution of the first three of these issues is, to a significant degree, beyond the scope of activities performed by an ANSP.

In recognition of the dependency upon the transponders to support future ATC operations it is necessary to ensure that they are working correctly and that any anomalies present when upgrades are introduced or resulting from equipment failures are promptly identified and swiftly resolved.

The prompt resolution of such issues is necessary for the ‘health’ of the infrastructure and to allow either old systems to be retired or new systems to be used in the most efficient manner. Retaining the ability to support legacy capabilities because some aircraft avionics do not meet published requirements is costly to all parties and improved mechanisms should be established to support prompt resolution of such issues.

Experience with the deployment of Mode S showed that resources should be allowed to verify the correct operations of avionic platforms before system can be considered for full operational use. Similarly that upgrades to transponder software to accommodate ADS-B functionality did not introduce new mistakes in Mode S functionality.

4.1.6.1 Transponder / Avionic Failures Hardware failures are a fact of life - components or connectors fail. Some such failures are readily apparent to ATC or the aircrew and can be ‘resolved’ by traditional means such as selecting standby


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transponder. With the increasing complexity of transponders and avionic components the failures can be more subtle and can only be identified by examining data off-line.

In recognition of the fact that transponders are critical elements in the surveillance chain Eurocontrol has established a dedicated Surveillance Avionic Analysis Group to focus upon the correct operation of transponders and the detection of anomalies. The service provided is seen by many in the aviation community as a key contributor to the performance assessment of the ATM infrastructure.

The prompt resolution of transponder /avionic failures is now an essential part of a modern ATM system.

4.1.6.2 Transponder / Avionic Configuration Design Error The introduction of additional complexity within transponder design such as the introduction of Mode S EHS or ADS-B capabilities has resulted in instances whereby all transponders of that version exhibit the same erroneous characteristics.

The scope of the Surveillance Avionic Analysis Group identified above was recently extended with the addition of ADS-B analysis work assessing the ADS-B equipage and quality (accuracy, latency, continuity etc). More than 1200 ADS-B equipped aircraft are currently monitored and many billions of ADS-B reports have been analysed so far.

Transponder anomalies can interfere with the correct operation of the 1030/1090MHz frequency band. The assessments of the 1030/1090 MHz RF environment performed by the Surveillance Avionic Analysis Group are made by using a specially developed software tool set to analyse surveillance data pertaining to ‘targets of opportunity’ recorded at a number of ground-stations across Europe.

A comprehensive assessment of an aircrafts transponder performance is conducted by analysing data provided by ANSP’s across Europe. If anomalous behaviour is identified the issue is investigated in more detail and, if necessary, the aircraft operator or transponder manufacturers are informed of the circumstances. The EUROCONTROL project members perform the role of focal point between ANSP’s, Aircraft Operators, EASA and Regulatory Authorities. Issues are managed through to resolution by working in concert with additional parties such as EASA and the Regulatory Authorities.

To conduct the investigative aspect of the task a unique laboratory test bed that fully exercises the capabilities and operations of any transponder has been developed. Using this test bed it is possible to resolve transponder anomalies without recourse to expensive flight trials.

Such activities are an essential part of a modern ATM system and that it is vital that it should continue to support the operational introduction of ADS-B.

4.1.6.3 System Design Error The performance of the surveillance system can be compromised by system design errors e.g. where the design specification for the integrated surveillance system does not permit the system to achieve full operational performance due to characteristics that were not taken into account in the system design. Such anomalies may occur through misinterpretation of standards or reference material or a mismatch between the specifications for system components.

EUROCONTROL, with support from other stakeholders, analyses potential system design errors and ensures that reference material is appropriately amended and that necessary corrective actions are undertaken.

4.1.7 Support the Development of MSPSR Products and Assoc iated Standards

To support the initial development of MSPSR, in either active and/or passive (PCL) configuration requires operational requirements that can be refined and translated into technical requirements, safety assessments, standards etc. The feasibility of the technique is accepted, the technology to support the design is available and industries are keen to proceed yet are reluctant in case their design does not meet Civil/Military ANSPs needs. It is desirable that SESAR OI Step CM-0406 Enabler CTE-S4b is resourced and the developments could be initiated.


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5 Changes to the SESAR Masterplan and the Supportin g Guidance Document.

The SESAR Definition Phase led to an initial European ATM Master Plan, which structures the future of ATM in Europe over the next decades. The initial SESAR ATM Master Plan (Ref Doc 2) was published in April 2008 and is currently undergoing a major revision. Where possible the information reflected in this document has been submitted for inclusion in the next version.

This section provides details for consideration for inclusion not only within subsequent versions of the SESAR ATM Masterplan but also supporting deliverables such as the Strategic Guidance document (Ref doc 3).

The ICAO GANIS initiative is also currently in progress. Both GANIS and SESAR are addressing ATM on a 2030 timescale. As there is a high degree of synergy between the surveillance aspects of both of these initiatives the general proposals outlined within this deliverable have been refined through the ICAO Aeronautical Services Panel (ASP) and are consistent with the proposals that the ASP submitted to the ICAO Technical Steering Group.

5.1 SESAR ATM Masterplan Due to the relatively high level of the SESAR ATM Masterplan (Ref Doc. 2) the changes identified as necessary to these documents are relatively minor. A similar level of description is anticipated in the forthcoming version. Detailed information supporting the ATM Masterplan is however contained with the supporting database.

The information provided in the tables contained within the standalone appendices 1 and 2 elaborates upon the correlation between operational improvements, enablers and ADS-B and other surveillance functionality. The tables were submitted for consideration within the activities to update the Masterplan and its supporting documentation. The information can be used to trace between Operational Improvements (OI) (where these are already designated – or for general efficiency improvements where no specific OI is stated) and the Enablers, Applications, certification documentation and surveillance component. Not all data items are required in all cells. The tables represent the current status but will be refined in line with on-going and future Masterplan and ADD activities.

The cells assigned a ‘TBA’ – To Be Assessed designation, are considered potential work areas to be considered when performing the Operational Improvements. In three areas subjects for new Operational Improvements are proposed. These are:

• Hybrid Surveillance

• Satellite ADS-B

• Integration of RPA into surveillance (Rather than a dedicated O.I a linkage to required surveillance activities could be achieved through the creation of a new Enabler)

Pending further refinement of the OIs and Enablers the following table identifies OIs with an anticipated link to surveillance activities. (Note that some pertain to airport surface applications). At the time that this deliverable was being written work was on-going to refine the content of the OIs within the activities to update the Masterplan and its supporting documentation.


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OI Step ID OI StepTitle

AO-0102 Automated Alerting of Controller in Case of Runway Incursion or Intrusion into Restricted Areas

AO-0104 Airport Safety Nets including Taxiway and Apron AO-0201 Enhanced Ground Controller Situational Awareness in all Weather Conditions AO-0205 Automated Assistance to Controller for Surface Movement Planning and Routing AO-0309 Minimum-Pair separations based on RSP AO-0402 Interlaced Take-Off and Landing AOM-0704 Tailored Arrival AUO-0302-A Provision of clearances using Datalink: Initial and time based implementation AUO-0302-C Provision of clearances using Datalink: performance based implementation

AUO-0303-A Revision of reference business/mission trajectory using datalink: initial and time based implementation.

AUO-0303-B Revision of reference business/mission trajectory using datalink: trajectory based implementation

AUO-0401 Air Traffic Situational Awareness (ATSAW) on the Airport Surface AUO-0402 Air Traffic Situational Awareness (ATSAW) during Flight Operations (AIRB)

AUO-0502 Enhanced Visual Separation on Approach (ATSA-VSA) AUO-0503 In-trail Procedure in Oceanic Airspace (ATSA-ITP) AUO-0504 Self-Adjustment of Spacing Depending on Wake Vortices AUO-0602 Guidance Assistance to Aircraft on the Airport Surface

AUO-0603 Enhanced Guidance Assistance to Aircraft on the Airport Surface Combined with Routing

AUO-0605 Automated Notification of Runway Incursion to Pilots and Controller CM-0203 Automated Flight Conformance Monitoring CM-0404 Enhanced Tactical Conflict Detection/Resolution and Conformance & Intent Monitoring CM-0406 Automated Assistance to ATC for Detecting Conflicts in Terminal Areas Operations CM-0601 Precision Trajectory Clearances -2D Based On Pre-defined 2D Routes CM-0603 Precision Trajectory Clearances -2D On User Preferred Trajectories

CM-0604 Precision Trajectory Clearances -3D On User Preferred Trajectories (Dynamically applied 3D routes/profiles)

CM-0701 Ad Hoc Delegation of Separation to Flight Deck - In Trail Follow & In trail Merge Procedure (ASEP-ITF & ITM )

CM-0702 Ad Hoc Delegation of Separation to Flight Deck - Crossing and Passing CM-0704 Self Separation in Mixed Mode CM-0801 Ground Based Safety Nets (TMA, En Route)

CM-0803 Enhanced TCAS compliant with change 7.1

CM-0804 ACAS Adapted to New Separation Modes DCB-0208 Dynamic ATFCM using RBT

IS-0303-A Use of onboard 4D trajectory data to enhance ATM ground system performance: initial and time based implementation

IS-0303-B Use of onboard 4D trajectory data to enhance ATM ground system performance trajectory based implementation

IS-0305 Automatic RBT Update through TMR TS-0103 Controlled Time of Arrival (CTA) through use of datalink

TS-0105 ASAS Sequencing and Merging as Contribution to Traffic Synchronization in TMA (ASPA-S&M)

TS-0106 Multiple Controlled times of Over-fly (CTOs) through use of data link

TS-0107 ASAS Manually Controlled Sequencing and Merging

Table 7: Operational Improvements Placing Requirements Upon Surveillance


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5.2 Subjects for inclusion in the SESAR ATM Masterp lan Subjects for R&D assessment that were not previously identified in the ATM Masterplan or the scope of SESAR activities that have being identified in the course of the 15.04.01 project are identified. These include:

• The feasibility of Satellite ADS-B as a means to provide surveillance initially in oceanic and low density airspace but possibly extending into higher density airspace,

• The development of Hybrid ACAS (also known as Hybrid Surveillance), or ‘Improved Hybrid ACAS’ offers, by using ADS-B information to reduce the usage of 1030/1090 MHz spectrum by ACAS, major savings in RF usage of the 1090MHz band. This development alone could make a significant improvement in spectrum occupancy and should therefore be considered as a subject for further development.

• The development of MSPSR – previously foreseen in ATM Masterplan V1 but not yet developed.

• The integration of RPA into surveillance.

• The development of improved modulation techniques for 1090MHz transmissions – to open up the possibility of extensive bandwidth available to support the transmission of new Aircraft Derived Data parameters.

Some of the above technologies may be initiated or become available in the near future through private venture funded developments or activities initiated through bodies such as ICAO or RTCA.

Whilst beyond the scope of ATM Research and more into deployment activities the following tasks are considered necessary to support and maintain the ‘health’ of the surveillance infrastructure. They are thus also identified for inclusion and further consideration.

• The need for monitoring and analysis of avionics supporting surveillance applications to safeguard the quality of the data being broadcast from aircraft.

• The need for monitoring of the 1030/1090 MHz usage and, as necessary, the establishment of appropriate mitigations.

5.3 Strategic Guidance in Support of the European A TM Master Plan

The initial European ATM Master Plan (Ref Doc 2) was supplemented by the ‘Strategic Guidance in Support of the Execution of the European ATM Master Plan’ (Ref Doc 3).

The strategic guidance document was produced to both support the implementation and development of the Master Plan and to describe how to achieve set targets.

This “Strategic Guidance in support of the Execution of the European ATM Master Plan” is structured around four elements of the ATM System: Performance, Network, Information Management and Infrastructure. The document provides a consolidated overview of how the European ATM System will accommodate the forecasted demand and respond to Stakeholder needs.

Regarding the topic of surveillance the Strategic Guidance in Support of the Execution of the ATM Master Plan document states:

• From the current situation, where mainly Mono-pulse SSR, SSR Mode-S and Primary Surveillance Radar (PSR) are widely in operational use, the surveillance infrastructure will evolve and be rationalised to achieve a higher performance, cost-efficiency and spectrum efficiency.

• It will be driven not only by the operational requirements but also the availability of new techniques and systems, such as Wide Area Multilateration, Automatic Dependent Surveillance etc. which will enable rationalisation of the ground infrastructure and development of new applications such as airborne surveillance.

• The vision for ground surveillance in en-route and terminal areas is the combination of ADS-B with independent surveillance, the latter provided by MSSR or Mode S or Wide Area


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Multilateration. Where there is still a need for Primary Surveillance radars, it could be fulfilled by the spectrum efficient Multi-static PSR (MSPSR).

• Airborne ADS-B systems will be available as enablers of the new separation modes (from airborne traffic situational awareness through spacing and separation to ultimately self-separation). These airborne applications will require changes in the avionics (“ADS-B Out” and “ADS-B In”) to process and display the air situation picture to the pilot.

• For airports, a locally optimised mix of the available technologies, i.e. airport Multilateration, Surface Movement Radars and ADS-B, will enable A-SMGCS systems and integrated airport operations. This includes the availability of surveillance information on a moving map, using an HMI in the cockpit and in surface vehicles.

• A rationalised (i.e. cost-efficient and spectrum efficient) ground surveillance infrastructure can be foreseen to be gradually deployed, using the opportunities offered by the new technologies.

The surveillance infrastructure foreseen within the Strategic Guidance document remains valid with a consideration regarding whether mono-pulse SSR (MSSR) techniques should be considered for long term retention. Only minor adaptation regarding Satellite ADS-B and an update regarding the legislative status of avionics is required. (Any subsequent version of the Strategic Guidance document requiring further detail e.g. regarding spectrum management should be based upon the proposals contained within the SESAR WP15.04.01 deliverables).


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6 Conclusions The whole of ATM is experiencing rapid change and increasingly demanding challenges. Introducing the changes that are necessary to ensure a surveillance infrastructure capable of meeting the demands of 2030 requires contribution and cooperation from a wide range of stakeholders. This report describes the drivers for change and how the surveillance infrastructure is foreseen to evolve over the next 20 years.

Further developments to existing surveillance technologies will improve the efficiency of techniques currently in use. The emergence of new techniques offer further improvements and present Air Navigation Service Providers (ANSPs) with additional tools in their portfolio however the foundations needed to support the diverse performance requirements for the future surveillance infrastructure are already available.

The activities conducted in recent years have established a solid foundation. Applying a combination of the rationalisation methodology (See SESAR WP15.04.01 D09-001 (Ref doc 1)) and an exploitation of the technological advances that are detailed within this document will ensure that the surveillance infrastructure can continue to meet the requirements placed upon it both today and into the future.


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7 Referenced Documents

Ref Title Latest version / date

1 SESAR 15.04.01 Document D09-001 Rationalisation of the Surveillance Infrastructure

Edition 00.02.00 May 2012

2 European Air Traffic Management Master Plan

(Note: This edition is currently undergoing a major review that is scheduled for publication in 2012)

Edition 1.0 March 2009

3 Strategic Guidance in Support of the Execution of the European ATM Master Plan

Version 1.0 May 2009

4

Commission Regulation No 691/2011 (amending 691/2010) laying down a performance scheme for Air Navigation Services and Network Functions in Europe. (Informally known as the NM IR)

Version published 8th August 2010

5

Commission Implementing Regulation (EU) No 1207/2011 laying down requirements for the performance and the interoperability of surveillance for the single European sky. (Informally known as the SPI IR)

Version published 22nd November 2011

6

Commission Implementing Regulation (EU) No 1206/2011 laying down requirements on aircraft identification for surveillance for the single European sky. (Informally known as the ACID IR)

Version published 22nd November 2011

7

Commission Regulation (EU) No 1332/2011 laying down common airspace usage requirements and operating procedures for airborne collision avoidance. (Informally known as the ACAS IR

Version published 16th December 2011

8 ICAO EUR Regional Supplementary Procedures Doc 7030 5th Edition 2008

9 EUROCONTROL Specification for ATM Surveillance System Performance (Vols 1 and 2)

(Document identifier: EUROCONTROL-SPEC-0147)

Edition 1.0 Dated 30/03/2012

10 SESAR WP15.01.06 D3 Spectrum Strategy 00.01.01 November 2011

11 SESAR WP15.01.06 D26 Aeronautical Spectrum Pricing 00.01.02 February 2011

12 EUROCONTROL Long-Term Forecast of IFR Flight Movements 2010 to 2030 report

V1.0 December 2010

13

EUROCAE ED-102A MOPS for 1090 MHz Extended Squitter Automatic Dependent Surveillance - Broadcast (ADS-B) and Traffic Information Services - Broadcast (TIS-B) (See also RTCA Do 260B)

Version Published January 2012

14 DRAFT form of CS-ACNS Not yet published

15

Commission Regulation (EU) N° 262/2009 laying down requirements for the coordinated allocation and use of Mode S interrogator codes for the single European sky. (Informally known as the MSI IR)

Version published 31st March 2009

16 Procedures for Air Navigation Services — Air Traffic Management (PANS-ATM, Doc 4444),

15th Edition November 2007


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Ref Title Latest version / date

17 Alternative Detection techniques to Supplement PSR Coverage Eurocontrol Report TR6/SR/PST-041/07

Initial version

February 2007

18 MSPSR – An examination of Alternative frequency bands Eurocontrol Report No 72/07/R/376/U

Issue 1.2

July 2008

19 EUROCAE ED-102 Minimum Operational Performance Standards for 1090 MHz Automatic Dependent Surveillance - Broadcast (ADS-B) and Traffic Information Services (TIS-B)

Version Published November 2000

20 EUROCAE ED129 Technical Specification for a 1090 MHz Extended Squitter ADS-B Ground Station

Version Published June 2010

21 EUROCAE ED-126 Safety, Performance and Interoperability Requirements Document for ADS-B-NRA Application

Version Published December 2006

22 EUROCAE ED161 Safety, Performance and interoperability requirements for ADS-B in Radar Airspace,

Version Published September 2009

23 Aeronautical Surveillance Manual ICAO Doc 9924 First Edition - 2011

24 P15.01.06-D18 Multi-static ATM surveillance radar band need report.

Edition 00.01.00 July 2011

25 European Commission Regulation No 550/2004 – on the provision of air navigation services in the single European sky (the service provision Regulation)

Version published 10th March 2004

26 RTCA Minimum Operational Performance Standards for Traffic Alert and Collision Avoidance System II (TCAS II) Hybrid Surveillance DO-300

Version published 13th December 2006


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Appendix A Acronyms and Terminology Term Definition

ACAS Airborne Collision Avoidance System

ACID Aircraft Identification

Act Actual (when used in Figure 1: Long Term Trend in European IFR Air Traffic (Source: Eurocontrol) of this deliverable)

ADD Aircraft Derived Data

ADS-B Automatic Dependant Surveillance - Broadcast

AIC Aeronautical Information Circular

AIP Aeronautical Information Publication

ANSP Air Navigation Service Provider

ARTAS ATM Surveillance Tracker and Server System

ASTERIX All-purpose Structured EUROCONTROL Surveillance Information Exchange (formerly "All-purpose Structured EUROCONTROL Radar Information Exchange")

ATC Air Traffic Control

ATM Air Traffic Management

ATS Air Traffic Services

ATSAW Air Traffic Situational Awareness

CAA Civil Aviation Authority (plus note that NSA is the term used within this document to describe the Regulatory Authority)

CNS Communications, Navigation and Surveillance

DAP Downlinked Aircraft Parameter (see also ADD)

DF Direction Finder

EATMN European Air Traffic Management Network

E-ATMS European Air Traffic Management System

EASA European Aviation Safety Agency

ECAC European Civil Aviation Conference

ELS Elementary Surveillance (as in Mode S ELS)

EHS Enhanced Surveillance (as in Mode S EHS)

ES Extended Squitter


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Term Definition

EU European Union

FAB Functional Airspace Block

FDPS Flight Data Processing System

FMS Flight Management System

FOC Full Operational Capability

FRUIT False replies unsynchronised in time

GAT General Air traffic

GPS Global Positioning System

GSM Global System for Mobile Communications

GVA Geometric Vertical Accuracy

IC Interrogator Code

ICAT II Code Allocation Tool

ICAO International Civil Aviation Organisation

IFF Interrogator Friend / Foe

IFR Instrumented Flight Rules

II Interrogator Identifier

IOC Initial Operational Capability

IP Internet Protocol

IR Implementing Rule

JAA Joint Aviation Authorities

JTSO JAA Technical Standing Order

MCP/FCU Mode Control Panel / Flight Control Unit

MICOG, Mode S IC Coordination Group

MOPS Minimum Operational Performance Specification

MSI IR Mode S Interrogator Code Allocation Implementing Rule

MSPSR Multi-Static Primary Surveillance Radar

MSSR Monopulse SSR

MTCD Medium Term Conflict detection


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Term Definition

MTF Medium term forecast (when used in Figure 1: Long Term Trend in European IFR Air Traffic (Source: Eurocontrol) of this deliverable)

MTOM Maximum Take Off Mass

MUAC Maastricht Upper Area Control Centre

NACp Navigation Accuracy Category for Position

NACv Navigation Accuracy Category for Velocity

NIC Navigation Integrity Category

NM Nautical Mile

NMF IR Network Management Function Implementing Rule

NRA Non-Radar Areas

NSA National Supervisory Authority. The responsibility of the NSA’s is as described in European Commission 550/2004 Article 2(1). (See ref doc 25)

OAT Operational Air Traffic

PRB Performance Review Board

PRF Pulse Repetition Frequency

PSR Primary Surveillance Radar

RAP Recognised Air Picture

RPA Remotely Piloted Aircraft

SARPs (ICAO) Standards and Recommended Practice

Sc A Scenario A (when used in Figure 1: Long Term Trend in European IFR Air Traffic (Source: Eurocontrol) of this deliverable)

Sc C Scenario C (when used in Figure 1: Long Term Trend in European IFR Air Traffic (Source: Eurocontrol) of this deliverable)

Sc D Scenario D (when used in Figure 1: Long Term Trend in European IFR Air Traffic (Source: Eurocontrol) of this deliverable)

Sc E Scenario E (when used in Figure 1: Long Term Trend in European IFR Air Traffic (Source: Eurocontrol) of this deliverable)

SDA System Design Assurance

SESAR Single European Sky ATM Research Programme

SESAR Programme The programme which defines the Research and Development activities and Projects for the SJU.


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Term Definition

SI Surveillance Identifier

SIL Source Integrity Level

SJU SESAR Joint Undertaking (Agency of the European Commission)

SJU Work Programme The programme which addresses all activities of the SJU Agency.

SPI Special Pulse (Position) Identification (SSR)

SPI IR Surveillance, Performance and Interoperability Implementing Rule

SSR Secondary Surveillance Radar

STCA Short term Conflict Alert

TCAS Traffic Alert and Collision Avoidance System (see also ACAS)

TMA Terminal Manoeuvring Area

UTC Coordinated Universal Time

VFR Visual Flight Rules

VLJ Very Light Jet

WAM Wide Area Multilateration

WGS World Geodetic System


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Appendix B Definitions

B.1Surveillance Terms Aeronautical Surveillance System is defined in ICAO Doc 9924 (Ref Doc. 23) as a system that “provides the aircraft position and other related information to ATM and/or airborne users. In most cases, an aeronautical surveillance system provides its user with knowledge of “who” is “where” and “when.” Other information provided may include horizontal and vertical speed data, identifying characteristics or intent. The required data and its technical performance parameters are specific to the application that is being used. As a minimum, the aeronautical surveillance system provides position information on aircraft or vehicles at a known time.

The requirements for ATS surveillance systems are contained in the Procedures for Air Navigation Services — Air Traffic Management (PANS-ATM, Doc 4444), Chapters 6 and 8. (Ref Doc 16)”.

The aeronautical surveillance system defined in ICAO Doc 9924 comprises several elements which will be operated based on the requirements of a specific application. Neither the applications nor the end-users are part of the aeronautical surveillance system.


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Surveillance data sources

Interface to Surveillance data users

Cooperative and remote Surveillance sub-system

Surveillance data compilation

Surveillance data transmission

Local Surveillance sub-system

Surveillance Sensor(s)/Receiver(s)

Surveillance Data Processing

Surveillance

SystemRadio Frequency (RF) data link(s)

Figure 5: Aeronautical surveillance system

This project focuses upon those ground-based components comprising the ICAO term of ‘local surveillance sub-system’ – namely the surveillance sensor(s)/receiver(s) and surveillance data processing.

The surveillance service delivered to ground users may be based on a number of techniques:

Independent Non-Cooperative Surveillance (as defined in ICAO 9924 – Ref Doc 23)

The aircraft position is derived from measurement not using the cooperation of the remote aircraft. An example is a system using PSR, which provides aircraft position but not identity or any other aircraft data.


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Independent Cooperative Surveillance (as defined in ICAO 9924 – Ref Doc 23)

The position is derived from measurements performed by a local surveillance subsystem using aircraft transmissions. Aircraft-derived information (e.g. pressure altitude, aircraft identity) can be provided from those transmissions.

Dependent Cooperative Surveillanc e (as defined in ICAO 9924 – Ref Doc 23)

The position is derived on board the aircraft and is provided to the local surveillance subsystem along with possible additional data (e.g. aircraft identity, pressure altitude).

The table below summarises the categories that the various existing and new ground-based air traffic Surveillance sensors fall into:

Air traffic surveillance sensor

Non Cooperative

Independent Primary Surveillance Radar (PSR)

Multi-Static Primary Surveillance Radar (MSPSR)

Independent Secondary Surveillance Radar (SSR) Mode A/C and Mode S

Wide Area Multilateration (WAM) system MultiLATeration (MLAT) system

Cooperative

Dependent Automatic Dependent Surveillance Broadcast (ADS-B)

Table 8: Categories of air traffic surveillance sensors

Composite Forms of Surveillance are means whereby two or more surveillance techniques are co-located to achieve either benefits in cost (deploying and maintaining at a single site may be cheaper than for a widely distributed set of systems) or which could bring functional benefits through the sharing of surveillance data (e.g. ADS-B collocated with a Mode S ground station could achieve RF efficiencies and improved detection capabilities).


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B.2 Miscellaneous Terms Air Navigation Service Provider means any public or private entity providing air navigation services for general and / or operational air traffic.

Aircraft Derived Data

Different cooperative surveillance technologies obtain different information from the aircraft.

In its simplest form, the Mode A and Mode C information provided by the aircrafts SSR transponder can be classified as aircraft derived data or down-linked aircraft parameters.

When implemented using SSR Mode-S Elementary Surveillance, the following Aircraft Parameters may be extracted from the aircraft:

(a) ICAO 24-bit address.

(b) Aircraft identification.

(c) Mode A code.

(d) Special Position Indication (SPI)

(e) Emergency status (General emergency, Radio communications failure, Unlawful interference)

(f) Pressure altitude.

(g) ACAS Active resolution advisories when the aircraft is equipped with TCAS II (For aircraft that require TCAS II, the Resolution Advisory discrete will need to be transmitted by the transponder (ICAO Annex 10, Vol IV))

(h) flight status (on the ground or airborne)

(i) Data link capability report:

• Airborne collision avoidance system (ACAS) capability,

• Mode S specific services capability,

• Aircraft identification capability,

• Squitter capability,

• Surveillance identifier capability,

• Common usage Ground Initiated Comms.-B (GICB) capability report (indication of change)

• Mode S subnetwork version number

(j) common usage GICB capability report


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When implemented using SSR Mode-S Enhanced Surveillance, the following current or short term Aircraft Parameters (also commonly known as Downlinked Aircraft Parameters – DAPs) may be extracted from the aircraft:

(a) Mode Control Panel / Flight Control Unit (MCP/FCU) Selected altitude.

(b) Roll angle.

(c) True track angle.

(d) Ground speed.

(e) Magnetic heading.

(f) Indicated airspeed (IAS) or mach number.

(g) Vertical rate (Barometric or Baro-inertial).

(h) Barometric pressure setting (minus 800 hectoPascals).

(i) Track angle rate or true airspeed if track angle rate is not available.

The surveillance parameters delivered by ADS-B include:

(a) ICAO 24-bit address.

(b) Aircraft identification.

(c) Mode A code.

(d) Special Position Indication (SPI)

(e) Emergency status (General emergency, No communications, Unlawful interference)

(f) ADS-B version number (=2).

(g) ADS-B emitter category.

(h) Geodetic horizontal position (WGS84 latitude and longitude), both while airborne or on the ground.

(i) Geodetic horizontal position quality indicators (corresponding to the integrity containment bound (NIC), 95% accuracy bound (NAC

p), Source Integrity Level (SIL) and System Design Assurance level (SDA)).

(j) Pressure altitude.

(k) Geometric altitude in accordance with the World Geodetic System revision 1984 (WGS84) (provided in addition and encoded as a difference to pressure altitude).

(l) Geometric vertical accuracy (GVA).

(m) Velocity over ground, both while airborne (East/West and North/South Airborne Velocity over ground) or on the ground (Surface Heading/Ground Track and Movement).

(n) Velocity quality indicator (corresponding to Navigation Accuracy Category for velocity (NACv).


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(o) Coded aircraft length and width.

(p) Global Positioning System (GPS) antenna offset.

(q) Vertical rate: barometric vertical rate when the aircraft is required and capable to transmit this data item via the Mode S protocol, or Global Navigation Satellite System (GNSS) vertical rate.

(r) Mode Control Panel / Flight Control Unit (MCP/FCU) Selected altitude using the same source as for the same parameter specified in the Mode S EHS ADDs when the aircraft is required and capable to transmit this data item via the Mode S protocol.

(s) Barometric pressure setting (minus 800 hectoPascals) using the same source as for the same parameter specified in the Mode S EHS ADDs when the aircraft is required and capable to transmit this data item via the Mode S protocol.

(t) ACAS Active resolution advisories when the aircraft is equipped with TCAS II

ATM Security

ATM security is defined as “Protective measures against both direct and indirect threats, attacks and acts of unlawful interference to the ATM System6”. This includes the role of the ATM system to support aircraft that are subject to unlawful interference and to maintain the safety of nearby aircraft. Accordingly, ATM security concerns three aspects:

• Protection of ATM facilities and systems (e.g. infrastructure, information, operational capabilities) against attacks;

• Prevention of mis-use of the ATM system for criminal acts;

• Detection of an incident (e.g. a terrorist threat or criminal activity), reporting to appropriate authorities (e.g. air defence or police) and orderly response, which entails mitigation of the effects, activation of contingency measures and recovery actions.

Automatic Dependent Surveillance – Broadcast (ADS-B )

ADS-B is a surveillance technique in which an appropriately equipped aircraft periodically broadcasts its position and other relevant information to potential ground stations and other aircraft with ADS-B-in equipment.

Surveillance Data Users

The users of Surveillance data include:

• Oceanic ATM Centres

• En-Route ATM Centres

• TMA/Approach ATM Units

• Airports/Tower ATM & Ground Traffic Management Units

• Military Centres

• Enhanced Tactical Flow Management System

• Data processing systems such as Flight Data Processing Systems

• ATM Tools, such as Short Term Conflict Alert

• The target (in the case of ADS-B In)

• Non ATM functions (e.g. Search and Rescue).

6 NEASCOG: ATM Security Strategy, AC/92 (NEASCOG)D(2006)0001, 13 April 2006


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