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The Global Positioning System:Serving the World
July 19, 2006
Jason Y. Kim, Senior AdvisorNational Space-Based Positioning, Navigation, and Timing (PNT) Coordination OfficeWashington, D.C., USA
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2National Space-Based PNT Coordination Office, USA
Overview
Introduction• U.S. Policy• GPS Performance• Next-Generation GPS• International Cooperation
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3National Space-Based PNT Coordination Office, USA
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
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4National Space-Based PNT Coordination Office, USA
U.S. Augmentations
Nationwide Differential GPS Wide Area Augmentation System
Local Area Augmentation SystemContinuously Operating Reference Stations
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5National Space-Based PNT Coordination Office, USA
International Augmentations
Differential GPS Networks
International GNSS Service
Space-Based Augmentation Systems
Global Differential GPS System
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6National Space-Based PNT Coordination Office, USA
Commercial GPS Applications Span Commercial GPS Applications Span A Wide Range of Economic ActivitiesA Wide Range of Economic Activities
Satellite Operations
CommunicationsNetwork
Synchronization
Surveying & Mapping
Fishing & BoatingOffshore
Drilling
Recreation
Trucking & Shipping
Personal Navigation
Aviation
Railroads
Power GridManagement
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7National Space-Based PNT Coordination Office, USA
New Commercial Applications Are Developed Every Day
• Open pit mining• Child safety• Automatic snowplow
guidance• Spacecraft control• Power grid management• Wireless mobile applications
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8National Space-Based PNT Coordination Office, USA
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 Future
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9National Space-Based PNT Coordination Office, USA
Overview
• IntroductionU.S. Policy• GPS Performance• Next-Generation GPS• International Cooperation
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10National Space-Based PNT Coordination Office, USA
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
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11National Space-Based PNT Coordination Office, USA
Space-Based PNT Policy Objectives
• Provide civil GPS and augmentations free of direct user fees on a continuous, worldwide basis
• Provide open, free access to information needed to use civil GPS and augmentations
• Improve performance of GPS and augmentations– Meet or exceed that of international systems– Improve resistance to interference for civil, commercial,
homeland security, and scientific users worldwide• Seek to ensure that international space-based PNT
systems are interoperable with civil GPS and augmentations– Or, at a minimum, are compatible
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12National Space-Based PNT Coordination Office, USA
Space-Based PNT Policy Objectives
• Provide uninterrupted access to U.S. space-based PNT services for U.S./Allied national security purposes
• Improve capabilities to deny hostile use of PNT without unduly disrupting civil and commercial access
• Maintain GPS as a component of multiple sectors of the U.S. Critical Infrastructure– Plan for backup capabilities and services
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13National Space-Based PNT Coordination Office, USA
Organizational Structure
WHITE HOUSE
NATIONALSPACE-BASED PNT
EXECUTIVE COMMITTEE
Co-Chairs: Defense, Transportation
ADVISORYBOARD
Sponsor: NASA
Defense
Transportation
State
Commerce
Homeland Security
NASA
Joint Chiefs of StaffCOORDINATION
OFFICEHost: Commerce
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14National Space-Based PNT Coordination Office, USA
Overview
• Introduction• U.S. PolicyGPS Performance• Next-Generation GPS• International Cooperation
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15National Space-Based PNT Coordination Office, USA
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)
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16National Space-Based PNT Coordination Office, USA
Civil GPS Performance Standards
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 standard
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17National Space-Based PNT Coordination Office, USA
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
.
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18National Space-Based PNT Coordination Office, USA
GPS Performance with WAAS
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.
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
Augmented GPS fulfills rigorous user needs today
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19National Space-Based PNT Coordination Office, USA
Overview
• Introduction• U.S. Policy• GPS PerformanceNext-Generation GPS• International Cooperation
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20National Space-Based PNT Coordination Office, USA
Benefits of Next-Generation GPS
• 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• For all users:
– System-wide improvements in accuracy, availability, integrity, and reliability
– Backward compatibility• Maintains international competitiveness
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21National Space-Based PNT Coordination Office, USA
Evolution of GPS Performance
1990’s• L1 C/A Signal• Selective Availability On
100 m or better
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22National Space-Based PNT Coordination Office, USA
Evolution of GPS Performance
36 m or better
TODAY• L1 C/A Signal• Selective Availability Off• Improved Orbit Information• L2C Signal (1 satellite)
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23National Space-Based PNT Coordination Office, USA
Evolution of GPS Performance
1-3 m
NEXT GENERATION• L1 C/A Signal (legacy users)• Selective Availability Off• Improved Orbit Information• L1C, L2C, L5 Signals
Improved resistance to interference
Increased range for RTK applications
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24National Space-Based PNT Coordination Office, USA
Evolution of GPS Performance
~1 m?
NEXT GENERATION + COOPERATION
• L1 C/A Signal (legacy users)• Selective Availability Off• Improved Orbit Information• L1C, L2C, L5 Signals• GNSS Interoperability
Increased range for RTK applications
Improved satellite availability
Improved resistance to interference
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25National Space-Based PNT Coordination Office, USA
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
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26National Space-Based PNT Coordination Office, USA
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
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27National Space-Based PNT Coordination Office, USA
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
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28National Space-Based PNT Coordination Office, USA
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
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29National Space-Based PNT Coordination Office, USA
Overview
• Introduction• U.S. Policy• GPS Performance• Next-Generation GPS International Cooperation
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30National Space-Based PNT Coordination Office, USA
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
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31National Space-Based PNT Coordination Office, USA
Europe
• GPS-Galileo cooperation agreement signed in 2004
• Parties agreed to implement common signal on Galileo and GPS III
• Working groups established:– 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)
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32National Space-Based PNT Coordination Office, USA
Japan
• World’s largest consumer of GPS technology
• U.S.-Japan cooperation began in 1998
• Quasi-Zenith Satellite System (QZSS)– Regional system to complement,
augment GPS over Japan– Will freely broadcast all GPS signals– GPS-QZSS interoperability achieved
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33National Space-Based PNT Coordination Office, USA
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
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34National Space-Based PNT Coordination Office, USA
Brazil
•U.S. cooperating with DECEA on aviation uses of GPS
•Brazil Test Bed for WAAS capability– Operational since 2001– 1 master station, 5 reference stations– Heart of ICAO’s Caribbean and South
American Test Bed– Led to discovery of geomagnetic
equatorial ionosphere issue for GPS•GNSS Performance Monitoring
System– Needed to comply with ICAO regulations– Will utilize Brazil Test Bed and other sites
to monitor GNSS signals received in Brazilian airspace
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35National Space-Based PNT Coordination Office, USA
Brazil
•Rio de Janeiro testbed for Ground-Based Augmentation System– Galeão and Santos Dumont airports– Precision approaches with Hawker aircraft– Unique, challenging environment for testing:
geomagnetic equator, mountainous terrain, multiple airports, runways near water
• New CORS site in Fortaleza– Cooperation among U.S.
National Geodetic Survey, INPE, and two Brazilian universities
• SIVAM system for Amazon surveillance– U.S. firm played major role in
its development
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36National Space-Based PNT Coordination Office, USA
Brazil
• U.S. Government is interested in expanding cooperation to broader mutual interests– Civil applications beyond aviation– Free market access, nondiscrimination– International standards– Preliminary discussions held in 2003– Workshop hosted at AMCHAM São Paulo in 2004
Seeking to continue dialogue with Government of Brazil
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37National Space-Based PNT Coordination Office, USA
Summary
• U.S. policy encourages 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 scheduled
• International cooperation is a priority– Compatibility and interoperability are critical– Opportunity for greater U.S.-Brazil
partnership
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38National Space-Based PNT Coordination Office, USA
“Muito Obrigado!”
National Space-Based PNT Coordination Office6822 Herbert C. Hoover Building
Washington, D.C. 20230USA
[email protected]+1 (202) 482-5809
PNT.GOV