u.s. space-based positioning, navigation, and timing (pnt) policy and modernization china executive...

U.S. Space-Based Positioning, Navigation, and Timing (PNT) Policy and Modernization

China Executive Management Development Training (EMDT) MITRE, McLean, VA

25 July 2006

Michael ShawDirector

U.S. National Space-based PNT Coordination Office

2China Executive Management Development Training25 July 2006

Overview

• What is Space Based PNT and GPS

• How GPS and Its Augmentations Work

• GPS Performance

• Next-Generation GPS

• U.S. Policy

• International Cooperation


•Space Based PNT is GPS plus its augmentations

•GPS is a space-based radio-navigation system

– Satellites broadcast precise and synchronized time signals and data to allow users to estimate their position, velocity, and time

•Augmentations improve GPS performance

What is Space Based PNT and GPS?


The Global Positioning System

• Baseline 24 satellite constellation in medium earth orbit

• Global coverage, 24 hours a day, all weather conditions

• Satellites broadcast precise time and orbit information on L-band radio frequencies

• Two types of signals:– Standard (free of direct user fees)– Precise (U.S. and Allied military)

• Three segments: – Space– Ground control– User equipment


Operational Control Segment Facilities

Master Control StationMaster Control Station

FAIRBANKS

USNO WASH D.C.

NEW ZEALAND

ECUADOR

ARGENTINA

ENGLAND

BAHRAIN

SOUTH AFRICA

SOUTH KOREA

COLORADO SPRINGS

VANDENBERG, AFB

HAWAII

GAITHERSBURG

CAPE CANAVERAL

ASCENSION

DIEGO GARCIA

KWAJALEIN

TAHITI

AUSTRALIA

Alternate Master Control Station (AMCS) Ground Antenna (GA)

Monitor Station (MS)National Geospatial-Intelligence Agency (NGA) Tracking Station

Master Control Station (MCS) Backup Master Control Station (BUMCS)


U.S. Augmentations

Nationwide Differential GPS Wide Area Augmentation System

Local Area Augmentation SystemContinuously Operating Reference Stations


International Augmentations

Differential GPS Networks

International GNSS Service

Space-Based Augmentation Systems

Global Differential GPS System


Commercial GPS Applications Span

A Wide Range of Economic Activities

Commercial GPS Applications Span

A Wide Range of Economic Activities Satellite

OperationsSatellite

Operations

CommunicationsNetwork

Synchronization

CommunicationsNetwork

Synchronization

Surveying & MappingSurveying & Mapping

Fishing & BoatingFishing & BoatingOffshore

DrillingOffshore Drilling

RecreationRecreation

Trucking & ShippingTrucking & Shipping

Personal NavigationPersonal

Navigation

AviationAviation

RailroadsRailroads

Power GridManagementPower Grid

Management


―Navigation -- Aircraft, land

vehicles, ships, &

satellites)– Precise timing

– Surveying

– Map making – Science

– Hiking

– Driving

– Flying

– Cell phones (e.g. e 911 services)

– Farming

– Boating

– Fishing

– Tracking wildlife

– Atmospheric/Space weather

– Visually impaired

– Computer security

– Games

Example Applications


New Commercial Applications Are Developed Every Day

• Open pit mining• Child safety• Automatic snowplow

guidance• Spacecraft control• Power grid management• Wireless mobile

applications


GPS is a Global Public Service

• Free access to civilian signals– One-way broadcast, like FM radio

• Public domain documentation– Anyone can develop user equipment

• Worldwide utility providing consistent, predictable, dependable performance– Critical component of global information

infrastructure• Owned and operated by the U.S. Government

– Paid for by U.S. taxpayers– Guided at a national level as multi-use asset– Acquired and operated by Air Force on behalf of USG

Available Now—Empowering the FutureAvailable Now—Empowering the Future


Overview


• How GPS and Its Augmentations

Work

• GPS Performance


• U.S. Policy



GPS – How does it work?

•GPS receiver uses signal from at least four satellites to “triangulate” its position in space

•Receiver knows several pieces of information:

– Location of satellites

– Time satellite sent data

– Time it received data

– Velocity data travels to receiver

•Using this information, the receiver calculates its distance from the satellite and ultimately its position on the Earth

China Executive Management Development Training25 July 2006

How GPS Works

ReceiverReceiverReceiverReceiver

1 ON 3menu

2

Rockwell

4 5 6

7 WPT

8 POS

9 NAV

CLRMARK

0 OFF

NUM LOCK

FIX FOM 1N 42* 01” 46.12”W 091* 38’ 54.36”EL + 00862 ft

ZEROIZE

Time & O

rbit

Position

Tim

e & O

rbit

Po

sition

Time & O

rbit

Position

Calculates 3-Dimensional Location and Time

Tim

e &

Orb

it

Po

siti

on


Location Determination3D example

Intersection of two spheres is a circle


Location Determination3D example

Intersection of three spheres is two pointsThe receiver dismisses the point located in space, leaving only one possible position on the earth


So Why Do We Need 4 Satellites?

4 sec.

6 sec.

5 sec.

5 sec.

7 sec.

6 sec. • With

receiver’s “inaccurate” clock—need 4

• If receiver had built in atomic clock—need 3

• 4th satellite measurement allows receiver to solve for 4th unknown (correction factor)


Overview



• GPS Performance


• U.S. Policy



Constellation Status

• 16 Block II/IIA satellites

• 12 Block IIR satellites– Modernizing 8 remaining Block IIR

satellites

• 1 Block IIR-M satellite– Transmitting new second civil signal

• Continuously assessing constellation health to determine launch need– Next launch: September 2006

29 Operational Satellites (Baseline Constellation: 24)

29 Operational Satellites (Baseline Constellation: 24)


GPS IIR-1120 Mar 04

50th GPS Satellite

Providing worldwide position, navigation & timing

GPS IIR-1223 Jun 04

GPS IIR-1306 Nov 04

Recent Launches

GPS IIR-14(M)25 Sep 05

1st Modernized GPS Satellite


Civil GPS Performance Standard

U.S. commitments to civil GPS performance are documented in the GPS Standard Positioning Service Performance Standard (2001)

In support of the service availability standard, 24 operational satellites must be available on orbit with 0.95 probability (averaged over any day). At least 21 satellites in the 24 nominal plane/slot positions must be set healthy and transmitting a navigation signal with 0.98 probability (yearly averaged).

Performance Standard

Representative Performance

Global Accuracy All-in-View Horizontal 95% All-in-View Vertical 95%

13 m 22 m

4 m 6 m

Worst Site Accuracy All-in-View Horizontal 95% All-in-View Vertical 95%

36 m 77 m

6 m 10 m

System accuracy far exceeds current standardSystem accuracy far exceeds current standard


Improving GPS Performance with Augmentations

Augmentations enhance GPS accuracy, monitor integrity– Sub-centimeter accuracy for geodesy, geology, etc.– 2-5 cm accuracy for real-time positioning, surveying, etc.– <3 m vertical accuracy with 6 second time to alarm for aviation

.


U.S. Federal Aviation Administration developed the Wide Area Augmentation System (WAAS) to provide necessary accuracy, integrity, and availability to support flight operations during all phases of flight

Based on observations from January to March 2006. Results are valid when the Localizer Approach with Vertical Guidance (LPV) service is available. During this time frame, LPV was available 98% to 99% of the time.

GPS Performance with WAAS

Augmented GPS fulfills rigorous user needs todayAugmented GPS fulfills rigorous user needs today

Performance Standard

Representative Performance

Best Site Accuracy Horizontal 95% Vertical 95%

2.5 m 2.5 m

.677 m .914 m

Worst Site Accuracy Horizontal 95% Vertical 95%

2.5 m 2.5 m

1.078 m 1.574 m


Overview



• GPS Performance

• GPS Modernization

• U.S. Policy



Benefits of GPS Modernization

• For all users– System-wide improvements in accuracy, availability,

integrity, and reliability– Backward compatibility

• For civil users– Higher standalone accuracy– Robustness against interference– Improved indoor, mobile, and urban use– Interoperability with other GNSS constellations

• For military– Enhances navigation warfare

• Maintains international competitiveness


Block IIA/IIR Block IIIBlock IIR-M, IIF•Backward compatibility

•4th civil signal (L1C)•Increased accuracy•Increased anti-jam power

•Assured availability•Navigation surety•Controlled integrity•Increased security•System survivability

IIR-M: IIA/IIR capabilities plus

•2nd civil signal (L2C)•M-Code (L1M & L2M)

IIF: IIR-M capability plus•3rd civil signal (L5)•Anti-jam flex power

Basic GPS•Standard Service– Single frequency (L1)– Coarse acquisition

(C/A) code navigation•Precise Service– Y-Code (L1Y & L2Y)– Y-Code navigation

Increasing System Capabilities Increasing Defense / Civil Benefit

GPS Modernization Program


Second Civil Signal

• Designed to meet commercial needs

• Freely available since Dec 2005– Currently on 1 satellite– Will be on all future satellites

• Expected to generate over $5 billion in user productivity benefits

Increases accuracyfor consumers

Benefits existing professional receivers

Supports miniaturization, possible indoor use


Third Civil Signal

• Designed to meet demanding requirements for transport safety

• May also enable global, centimeter-level accuracy using new techniques

• Opportunity for international interoperability


Fourth Civil Signal

• Designed with international partners for interoperability

• Modernized civil signal at L1 frequency– Original signal retained for

backward compatibility

• More robust navigation across a broad range of user applications

• Improved performance in challenged tracking environments

Under trees

Inside cities


GPS III

• Next-generation satellites are needed to accommodate increasing capabilities

• Civil benefits– Provides operational capability for L2C and L5

• In combination with GPS IIR-M and IIF satellites

– Delivers L1C for interoperability with Galileo, QZSS

– Significant increase in system accuracy

– Improved availability of accuracy with integrity

• Revised acquisition strategy– Spiral development approach to reduce risk, increase

flexibility

– Separate contracts for space and ground segments to ensure best technology and most efficient implementation


GPS III Proposed Accuracy

• Draft System Specifications

• Includes the effects of receivers– Threshold = low-cost/low-performance receiver– Objective = high-cost/high-performance receiver

ACCURACY (95%) THRESHOLD OBJECTIVE

Horizontal 2.5 m 0.5 m

Vertical 4.5 m 1.1 m

Timing 5.7 ns 1.3 ns


Overview



• GPS Performance


• U.S. Policy



U.S. Policy History

• 1983: President Reagan offers free civilian access to GPS

• 1996: GPS declared a dual-use system under joint civil/military management

• 1997: Congress passes law requiring civil GPS to be provided free of direct user fees

• 2004: President Bush issues new U.S. policy on space-based PNT


Policy Objectives

• Provide space-based civil PNT services free of direct user fees on a continuous, worldwide basis

• Open, free access to information needed to use civil GPS and its augmentations

• Improve performance of GPS and its augmentations - improving global services– Ensure civil services exceed, or are at least equivalent

to, those of other international civil space-based PNT services

– Improve resistance to interference for civil, commercial, homeland security, and scientific users

• Seek to ensure that international PNT systems are interoperable with GPS and its augmentations– Or, at a minimum, are compatible


Organizational Structure

WHITE HOUSEWHITE HOUSE

NATIONALSPACE-BASED PNT

EXECUTIVE COMMITTEE

Co-Chairs: Defense, Transportation

NATIONALSPACE-BASED PNT

EXECUTIVE COMMITTEE

Co-Chairs: Defense, Transportation

ADVISORYBOARD

Sponsor: NASA

ADVISORYBOARD

Sponsor: NASA

DefenseDefense

TransportationTransportation

StateState

CommerceCommerce

Homeland SecurityHomeland Security

NASANASA

Joint Chiefs of StaffJoint Chiefs of StaffCOORDINATION

OFFICE

Host: Commerce

COORDINATIONOFFICE

Host: Commerce


Overview



• GPS Performance


• U.S. Policy



Global Navigation Satellite Services (GNSS) Expanding

• Sep 2005 – 2nd civil GPS signal

• Dec 2005 –first Galileo test satellite

• Dec 2005 –3 GLONASS satellites

• This year – European EGNOS operational

• Japan preparing for MSAS ops in 2007 and QZSS

• India moving forward with GAGAN and IRNS

• China Beidou, CompassInteroperability key to seamless global operationsInteroperability key to seamless global operations


U.S. Cooperation Strategy

• Provide civil GPS and augmentation services free of direct user fees on a continuous, worldwide basis

• Provide open, free access to information needed to develop equipment

• Improve performance of civil GPS and augmentations to meet or exceed that of international systems

• Encourage international development of PNT systems based on GPS

• Seek to ensure international systems are interoperable with civil GPS and augmentations– Or at a minimum, are

compatible

• Address mutual security concerns with international providers to prevent hostile use

Outlined in 2004 Presidential policy on space-based positioning, navigation, and timing (PNT)


U.S. GPS Cooperation

• Ongoing cooperation with Europe, Japan, Russia– Compatibility and interoperability

– National security

– Level playing field in global markets

• Seeking formal relations with Australia, India, Brazil

• Multilateral cooperation– U.N. International Committee on

GNSS

– ICAO, IMO, NATO


Europe

• In 2004, United States and European Community signed historic agreement on GPS-Galileo cooperation– Recognizes importance of compatibility/interoperability for all

parties

• Agreed to spectrally separate signals for military, civilian, and public regulated services

• Agreed to implement a common, open, civil signal on both Galileo and GPS III, free of direct user fees

• Working groups establishedto continue dialogue:– Compatibility & Interoperability– Trade & Commercial Applications– Next-Generation GNSS– Security Issues

June 26, 2004, press conference at U.S.-EU Summit in Ireland (U.S. Sec. of State Colin Powell, Irish Foreign Minister Brian Cowen, EU Vice-President Loyola De Palacio)


Japan

• World’s largest consumer of GPS technology

• U.S.-Japan cooperation began in 1998– Initially focused on interoperability with MSAS,

Japan’s GEO-based augmentation system– Promotes common principles such as free market

access– Annual plenary meetings, technical working

groups

• Current focus is on Quasi-Zenith Satellite System (QZSS)– Regional system to complement, augment GPS

over Japan– Will improve performance in urban canyons and

mountains– Will freely broadcast GPS L1C, L2C, L5 signals– GPS-QZSS interoperability achieved

MT-SAT used for MSAS


Russia

• Cooperation started in 2004

• Working groups are pursuing GPS-GLONASS interoperability– Enhanced PNT through combined

service

– Combined search and rescue capabilities

• Currently pursuing formal cooperation agreement

GLONASS satellite


International Committee on GNSS

• Multilateral group chartered through United Nations– First meeting: December 2005

• Purpose: Promote use of GNSS to improve efficiency and security of transport, search & rescue, geodesy, etc., particularly in developing countries– Coordination among providers to improve compatibility and

interoperability

– Assistance to developing countries in integration of PNT services

– Focal point for international information exchange

– Forum for addressing future user needs


Summary

• U.S. policy encourages and promotes worldwide use of civil GPS and augmentations

• GPS performance is better than ever and will continue to improve– Augmentations enable high performance today

– New GPS signal now available

– Many additional upgrades in the future

• International cooperation is a priority– Compatibility and interoperability are critical

– Opportunity for partnership with all nations


Contact Information

Michael E. Shaw, DirectorNational Space-Based PNT Coordination Office

Herbert C. Hoover Building, Room 6822 1401 Constitution Avenue, NWWashington, D.C. 20230 USA

Ph: (202) 482-5809Fax: (202) [email protected]

Presentation and other GPS information available:

www.pnt.gov

u.s. space-based positioning, navigation, and timing (pnt) policy and modernization china executive...

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