the global positioning system: serving the world

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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Overview

Introduction• U.S. Policy• GPS Performance• Next-Generation GPS• International Cooperation

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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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U.S. Augmentations

Nationwide Differential GPS Wide Area Augmentation System

Local Area Augmentation SystemContinuously Operating Reference Stations

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International Augmentations

Differential GPS Networks

International GNSS Service

Space-Based Augmentation Systems

Global Differential GPS System

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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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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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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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Overview

• IntroductionU.S. Policy• GPS Performance• Next-Generation GPS• International Cooperation

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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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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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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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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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Overview

• Introduction• U.S. PolicyGPS Performance• Next-Generation GPS• International Cooperation

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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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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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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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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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Overview

• Introduction• U.S. Policy• GPS PerformanceNext-Generation GPS• International Cooperation

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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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Evolution of GPS Performance

1990’s• L1 C/A Signal• Selective Availability On

100 m or better

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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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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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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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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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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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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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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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Overview

• Introduction• U.S. Policy• GPS Performance• Next-Generation GPS International Cooperation

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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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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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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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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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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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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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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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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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“Muito Obrigado!”

National Space-Based PNT Coordination Office6822 Herbert C. Hoover Building

Washington, D.C. 20230USA

pnt.office@pnt.gov+1 (202) 482-5809

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