01 - icao - gnss vulnerability rev ac · • chapter 5 of icao doc 9849 –unintentional...

GNSS VulnerabilityFrancisco Almeida da Silva – ICAO CNS Officer

ITU Satellite Symposium 2019 126 Sep 2019

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Global Navigation Satellite System

• Background on the introduction of GNSS in civil aviation use:

https://www.unitingaviation.com/strategic-objective/safety/introducing-the-global-navigation-satellite-system-in-civil-aviation-use/


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• GNSS supports positioning, navigation and timing(PNT) applications.

• For civil aviation, GNSS is already the foundation of performance-based navigation (PBN), automatic dependent surveillance – broadcasting (ADS-B) and automatic dependent surveillance – contract (ADS-C).

• Initial constellations: GPS and GLONASS (one frequency band).

• Two new constellations are underway: Galileo and BeiDou (two separate frequency bands).

• GPS and GLONASS are also being enhanced to use two bands.

• The ICAO Navigation System Panel (NSP) is currently developing Standard for this new generation of GNSS:

Dual-frequency, Multi-constellation (DFMC) GNSS

Global Navigation Satellite System


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GNSS Implementation • GPS was declared fully operational in 1993, and

several States approved the use of GPS guidance for instrument flight rules (IFR) en-route, terminal and non-precision approach (NPA) operations that same year.

• In 2011, ICAO adopted SARPs supporting GNSS operations based on augmenting core satellite constellation signals to meet safety and reliabilityrequirements.

• There are three augmentation systems defined in Annex 10: the aircraft-based augmentation system (ABAS), the satellite-based augmentation system (SBAS) and the ground-based augmentation system (GBAS).

ITU Satellite Symposium 201926 Sep 2019

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GNSS Vulnerability• GNSS signals from satellites are very weak at the receiver antenna

and are also susceptible to ionosphere effects.


GNSS Vulnerability

• Chapter 5 of ICAO Doc 9849– Unintentional interference– Intentional interference and spoofing– Spectrum regulation– Effects of the ionosphere and solar activity


GNSS Vulnerability• Unintentional interference

– There are a number of sources of potential interference to GNSS from both in-band and out-of-band emitters, including mobile and fixed VHF communications, harmonics of television stations, certain radars, mobile satellite communications and military systems.

– Many reported instances of GNSS interference have been traced to on-board systems, including VHF and satellite communications equipment and portable electronic devices. Such interference can be prevented by proper installation of GNSS avionics (e.g. shielding, antenna separation and out-of-band filtering), integration with other aircraft systems and restrictions on the use of portable electronic devices.


GNSS Vulnerability• Intentional interference and spoofing

– In an era when essentially all conventional navigation aids remain in service, and when all aircraft are still equipped to use them, there is little motivation to deliberately interfere with GNSS-based aviation services. As reliance on GNSS increases, however, the threat of intentional interference could increase.

– Of primary concern is the proliferation of jammers designed to defeat vehicle-tracking systems.

– Spoofing is the broadcast of GNSS-like signals that cause avionics to calculate erroneous positions and provide false guidance. While it is generally considered that the spoofing of GNSS is less likely than the spoofing of traditional aids because it is technically more complex, the availability of affordable software-defined radio is gradually turning it into a real threat.


GNSS Vulnerability

Effective spectrum management is the primary way to reduce the likelihood of unintentional and intentional interference with GNSS signals. This comprises creating and enforcing regulations/laws that control the use of spectrum and carefully assessing applications for new spectrum allocations.


ICAO Assembly (40TH Session) input papers


ICAO Assembly (40TH Session): from WP/82

The Assembly is invited to: a) urge States to:

1) apply necessary measures to avoid the commercialization / proliferation and the use of illegal transmitters such as jammers which may impact satellite‐based CNS systems;

2) Ensure close collaboration between aviation authorities, service providers, radio regulatory and spectrum enforcement authorities to ensure that this spectrum is free from harmful interference;

3) reinforce civil‐military collaboration regarding global navigation satellite system (GNSS) testing and other activities, which may impact satellite‐based CNS systems, with the air navigation services provider (ANSP) responsible for the affected airspace; and

4) consider, when assessing the interference risks associated with conflict zones, that the use of satellite‐based CNS systems can potentially be impacted beyond that zone.


Conclusions• GNSS has resulted in substantial safety, efficiency and capacity benefits and is a necessary

cornerstone of daily flight and ATM operations. Effective mitigations of harmful interference to GNSS will ensure that these benefits continue, and will help prevent interruptions of flights -resulting in better punctuality of global trade and enhanced satisfaction of the travelling public.

• Noting the importance of safety-of-life applications using GNSS, radio frequency spectrum allocations for GNSS signals are globally harmonized and legally protected under the Radio Regulation of the International Telecommunication Union (ITU). Article 4.10 of the Radio Regulations states that ITU member States recognize that the safety aspects of radio navigation and other safety services require special measures to ensure their freedom from harmful interference.

• Following the establishment of the GNSS RFI mitigation plan, ICAO continues its engagement on this critical issue, with a view to developing guidelines and best practices for use at the State, regional and global levels to mitigate safety risks related to any civil or military GNSS testing activities or other activities which may impact CNS systems.

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Thank You

Francisco Almeida da [email protected]+ 51 1 611‐8686 ext. 107

26 Sep 2019 ITU Satellite Symposium 2019

01 - icao - gnss vulnerability rev ac · • chapter 5 of icao doc 9849 –unintentional...

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