GLOBAL POSITIONING SYSTEM

Space Enterprise Council Capitol Hill Day14 March 2008

Major Charlie Daniels, U.S. Air ForceNational Coordination Office

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What You Know…

• Like the Internet, GPS is a critical component of the global information infrastructure

– Scalable applications enabling broad new capabilities – Facilitating innovations in efficiency, safety,

environmental, public security and science

• Over the past decade, GPS has grown into a global utility providing space-based positioning, navigation and timing (PNT)

– Consistent, predictable, dependable performance– Augmentations improve performance

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Briefing Overview

• GPS System

• GPS Applications

• GPS Modernization

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GPS Introduction

• Owned and operated by the U.S. Government– Paid for by U.S. taxpayers

– Managed at a national level as multi-use asset

– Acquired and operated by the U.S. Air Force on behalf of the U.S. Government per Title 10, Section 2281.

• GPS service is a one-way broadcast, like FM radio– Unlimited number of users

– Access to civilian GPS signals is free of direct user fees

• Public domain documentation– Available on an equal basis to users and industry

– Anyone in the world can develop GPS user equipment

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GPS Segments

MonitorStationsMonitorStations

GroundAntennasGround

Antennas AFSCNAFSCN

Master Control StationMaster Control Station

Space Segment

User Segment

Control Segment

Satellite ConstellationSatellite Constellation

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

CAPE CANAVERAL

ASCENSION DIEGO

GARCIA

KWAJALEIN

TAHITI

Master Control Station (MCS) Advanced Ground AntennaMaster Control Station (MCS) Advanced Ground Antenna

Ground Antenna (GA)Ground Antenna (GA) Monitor Station (MS) Monitor Station (MS)

National Geospatial-Intelligence Agency (NGA) Tracking StationNational Geospatial-Intelligence Agency (NGA) Tracking Station

Alternate Master Control Station (AMCS)Alternate Master Control Station (AMCS)

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• Navigation message generation– Satellite position data

– Monitor L-Band signals

– Adjust GPS signal as needed

GPS Ground Control Segment

• Command & Control satellites– Perform maneuvers

– Monitor satellite health

The control segment keeps the GPS constellationoperating and performing within specification

The control segment keeps the GPS constellationoperating and performing within specification

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GPS User Segment

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• Unlimited– Broadcast system

– More users can join system

– U.S. & International

• Multi purpose – Civil

– Military

– Commercial

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GPS Space Segment

• 14 Block IIA satellites• 12 Block IIR satellites• 5 Block IIR-M satellites

– Transmitting new second civil signal (L2C)

– Transmitting new military signal (M code)

• Next launch: March 15, 2008

31 GPS Satellites Set Healthy (as of 10 Mar 08)(Baseline Constellation: 24)

31 GPS Satellites Set Healthy (as of 10 Mar 08)(Baseline Constellation: 24)

30 Years of SuccessFirst Operational Launch 22 Feb 1978

30 Years of SuccessFirst Operational Launch 22 Feb 1978

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Continuous Performance Improvement

Decreasing range error

PerformanceStandard

Year

Accuracy

Global GPS civil service performance commitmentcontinuously met since 1993

Global GPS civil service performance commitmentcontinuously met since 1993

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2

4

6

8

10

Yea

rs

Satellite 39 35 34 36 33 40 30 38 43 46 51 44

12

41 54 56

14

45

16

47 59 60 61 5325 26 27 32 37 52 58

GPS Constellation StatusSatellite Age as of March 2008

2423 55 57

BLOCK IIA BLOCK IIR BLOCK IIR-M

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GPS Applications

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• Civil/Commercial briefed earlier

• Military Applications– Force location– Navigation– Force employment– Weapon guidance– All weather ops– Satellite positioning– Comm network timing

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GPS – Force Multiplier

• WWII Schweinfurt-Regensburg Raids:– Dropped 24 million pounds of bombs to strike 5 ball bearing plants

• 376 B-17s

= 5 Targets Hit

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GPS III (Block III)• Increased accuracy • Increased signal

strength• Signal integrity• Search and Rescue• Common Galileo

signal (L1C)

Legacy (Block IIA/IIR)• Basic GPS• C/A civil signal (L1C/A)• Std Pos. Service• Precise Pos. Service• L1 & L2 P(Y) nav

Modernized (Block IIR-M)• 2nd civil signal (L2C)• M-Code signals

SatellitesModernized (Block IIF) • 3rd civil signal (L5)

Upgraded (AEP)• IIR-M IIF TT&C• WAGE, AII, LADO• New MCS/AMCS

Legacy• TT&C• L1 & L2 monitoring

Control Systems

User Equipment

Upgrading• Military User Equipment

OCX (Modernized)• New Architecture• L1C, L2C, L5, M-Code• Flex Power

All Segment – GPS Modernization

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Modernized GPS – New Signals

• Second civil signal (“L2C”)–Designed to meet commercial needs–Higher accuracy through ionospheric correction–Began with GPS Block IIR-M in Sep 2005; 24 satellites: ~2014

• Third civil signal (“L5”)–Designed to meet demanding requirements for transportation safety (safety-of-life)

–Begins with GPS Block IIF–First launch: ~2008 (GPS IIR-M Demo); ~2009 (GPS IIF); 24 satellites: ~2016

• Fourth civil signal (“L1C”)–Designed with international partners to enable GNSS interoperability–Begins with GPS Block III; First launch: ~2014; 24 satellites: ~2021

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Benefits of GPS Modernization

• System-wide improvements in accuracy, availability, integrity, and reliability to:

– Meet increasing civil, commercial and military demands

– Remain the pre-eminent space-based military PNT system

• Higher standalone accuracy

• More robust against interference

• Provides separate more secure Military signal

• Capability for second (L2C) and third (L5) civil signals

• Delivers L1C for interoperability with other GNSS

• Improved indoor, mobile, and urban use

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Summary

• GPS System– 3 Segments; Ground Control, Space and User

– Sustaining aging constellation while providing best accuracy

• GPS Applications– Unlimited civil/commercial global user capacity

– Military users

• GPS Modernization– Key to meeting emerging civil/commercial demands

– Key to remaining the preeminent military space-based PNT service

GPS – The World’s Gold Standard in Space-Based PNT Services

GPS – The World’s Gold Standard in Space-Based PNT Services

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Contact Info

Major Charles Daniels, U.S. Air ForceNational Coordination Office for Space-Based PNT

1401 Constitution Ave, NW, Room 6822Washington, DC 20230

Tele: 202-482-6726 Email: charles.daniels@pnt.gov

Web sites: http://pnt.govhttp://gps.gov