U.S. Programs & Policy

Ken AlexanderSenior Advisor, National Coordination Office

CNS/ATM 2008Armed Forces Communications and Electronics Association

and 853d Electronic Systems Group

Tampa, FloridaJune 26, 2008

2

Overview

• Introduction• Global Positioning System• GPS Augmentations/Backups• U.S. Policy• International Cooperation

3ENC-GNSS 04/23/08

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New Applications Evolving Every Day• Environmental Monitoring• Excavation/Open pit mining • Automatic snowplow

guidance• Child/Pet tracking• Spacecraft control• Wireless/Mobile

applications

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GNSS is Key to Scientific Monitoringof the Earth

To better understand the changes and complex dynamic processes of our home planet

To better understand the changes and complex dynamic processes of our home planet

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Keys to the Global Success of GPS

• Program Stability and Performance– Civil service performance commitment met continuously

since December 1993– Continuity of constellation and signals ensured through

Air Force operation and acquisition– Continuous improvements in accuracy, availability, etc.– Funding through U.S. taxpayers

• Policy Stability and Transparency– Open access to civil GPS signals, free of direct user fees– Open, free, and stable technical documentation– Market-based competition worldwide– Liberal export controls on GPS user equipment– National-level policy coordination including civil and

military leaders

• Commercial Entrepreneurship and Investment

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Overview

• Introduction• Global Positioning System• GPS Augmentations/Backups• U.S. Policy• 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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GPS Constellation Status

• 13 Block IIA• 12 Block IIR• 6 Block IIR-M

– Transmitting new second civil signal

• Continuously assessing constellation health to determine launch need– 2 Block IIR-M’s remaining– Next launch: September 2008

31 Operational SatellitesAs of June 1, 2008 (Baseline Constellation: 24)

31 Operational SatellitesAs of June 1, 2008 (Baseline Constellation: 24)

GPS is moving into its 4th Decade of Service

First Launch 22 Feb 1978

GPS is moving into its 4th Decade of Service

First Launch 22 Feb 1978

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4.64.3

3.02.7

2.11.8

1.51.1

0

1

2

3

4

5

6

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1990 1992 1994 1996 1997 1999 2001 2005

RM

S U

ser R

ange

Err

or (m

)

Continuous Performance Improvement

Decreasing range error

Year

Key measures of effectiveness to evaluate GPS services– Accuracy– Bounded inaccuracy– Integrity– Assured availability– Resistance to RF interference/jamming

Performance Standard

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USG Commitment to GPS

• Based on a constellation with 24 Nominal Plane/Slot Positions

• 24 Operational Satellites 95% (averaged over any day)

– All 24 may not be operating

– Not All SVs may be located in Primary Orbit Slots

• 21 of 24 Plane/Slot Positions must be set healthy and transmitting a navigation signal with 98% probability (averaged yearly)

• 6 meter User Range Error (URE)

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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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Recent GPS Improvements

• Expanded GPS ground network to triple amount of monitor data sent to control station– 10-15% improvement in accuracy of GPS data

broadcast

• Launched 3 modernized satellites in past 8 months– Largest GPS constellation size ever– Retiring old satellites improves overall GPS accuracy

• Transitioned to entirely new, modernized master control station– Improved operational flexibility and responsiveness– Added backup control station

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GroundAntenna

Master Control Station (Schriever AFB)

GPS Operational Control Segment (OCS)

AscensioAscensionn

Diego Diego GarciaGarcia

Cape Cape CanaveralCanaveralHawaiiHawaii

Kwajalein Kwajalein

Schriever Schriever AFB AFB

ColoradoColorado S KoreaS Korea

AustraliaAustralia

BahrainBahrain

S AfricaS Africa

EnglandEngland

ArgentinaArgentina

EcuadorEcuador

TahitiTahiti

USNOUSNO

AlaskaAlaska

MonitorStation

New New ZealanZealandd

Vandenberg Vandenberg AFB AFB

CaliforniaCalifornia

NGA Monitor Station

OCS Monitor Station

Ground Antenna Future Monitor Station

Master Control Station

Backup Master Control Station

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

strength• Signal integrity• Search and Rescue• Common Galileo

OS/GPS (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 (L1M, L2M)

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 EquipmentLegacy• Man Pack• MAGR, PLGR• RCVR-3A, 3S • OH, UH• FRPA, CRPA

Upgraded• DAGR• CSEL

• GAS-1• MAGR2K• GB-GRAM

Modernized• MUE• MSR

OCX Block 2• L1C

OCX Block 1 (Modernized)• New Architecture• L2C, L5, M-Code• Flex Power OCX Block 3/4)

• Spot Beam • Mission Planning• Near-real Time

Command and Control

All Segment – GPS Modernization

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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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Third Civil Signal (L5)

• Increasing interoperability – Galileo E5a, GLONASS, Compass,

QZSS, WAAS & other SBAS• Demonstration signal in 2008• 24 satellites by 2018

• Designed to meet demanding requirements for aviation safety– Uses highly protected Aeronautical Radionavigation Service

(ARNS) band• Wider bandwidth improves resistance to

interference• Signal Structure for enhanced performance• Higher power than other GPS signals

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GPS II and GPS IIIA

USER SEGMENT

CONTROL SEGMENT

SPACE SEGMENT

GPS SISINTERFAC

E

SIS Integrity: 1e-5/SV/hr

10 SVs Visible: 1e-4/hr

Augmentation

• RAIM

• DGPS

Accuracy: 1.0 – 4.0 m rms

Navigation Integrity: 1e-7/hr

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GPS Critical to Safety-of-Life Applications

Positioning Signal Integrity and Continuity Assurance (PSICA) is needed to ensure GPS IIIC meets stringent requirements for safety-of-life

(e.g., aviation) application

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GPS IIIC

USER SEGMENTCONTROL SEGMENT

SPACE SEGMENT

GPS SISINTERFA

CEAugmentation

• RAIM

• DGPS

SIS Integrity: 1e-8/SV/hr

10 SVs Visible: 1e-7/hr

SIS Accuracy: 0.25 m rms

Navigation Integrity: 1e-7/hr

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Goal of Global Navigation Satellite System Civil Interoperability

• Interoperability allows navigation with signals from four different systems with minimum additional receiver cost or complexity

GPS

QZSSGALILEO

GLONASS

Interoperable = Better Together than Separate

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GPS Summary

• Success in GPS sustainment & modernization– New capabilities delivering enhanced performance

– Developments on track to enhance space and control and user segments

• GPS is an excellent global navigation utility– Excellent cooperation with augmentation service

providers

– U.S. looks forward to working with all to ensure GNSS civil systems are interoperable for the benefit of all users

• U.S. is continuing to modernize and improve GPS– To remain the pre-eminent space-based PNT service

– To lead the future GNSS system-of-systems

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Overview

• Introduction• Global Positioning System• GPS Augmentations/Backups• U.S. Policy• International Cooperation

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Augmentations Improve GPS Performance

Enhanced accuracy• <1.5 m WAAS vertical accuracy

for aviation• 2-5 cm for real-time

positioning, surveying, etc.• <1 cm for geodesy, geology,

etc.

Integrity monitoring• 6 sec time to alarm for aviation

.

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U.S. Augmentations

Nationwide Differential GPS

Local Area Augmentation System

Continuously Operating Reference Stations

Wide Area Augmentation System

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International Augmentations

Differential GPS Networks

International GNSS Service Global Differential GPS System

Space-Based Augmentation Systems

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Wide Area Augmentation System

• Two replacement satellites launched in 2005– Dual coverage over United

States

– Ranging improves availability

– Integrity corrections for clock, ephemeris, and ionosphere

• Service expanded into Canada and Mexico– Reference stations in

Mexico (5) and Canada (4) support operations since 2007

Telesat107W

Intelsat133W

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Enhanced Loran as National Backup to GPS

• Enhanced Loran (eLoran) announced as national backup to GPS for PNT in Feb 2008– As recommended by

Independent Assessment Team and National Executive Committee

– Funded through Department of Homeland Security

• Will replace legacy Loran-C system

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Overview

• Introduction• Global Positioning System• GPS Augmentations/Backups• U.S. Policy• International Cooperation

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U.S. Policy History

• 1978: First GPS satellite launched

• 1983: President offered free civilian GPS access to GPS

• 1996: Established joint civil/military GPS management

• 1997: Congress passes law providing civil GPS access free of direct user fees

• 2000: President set Selective Availability to “Zero”

• 2004: President issues U.S. Policy on Space-Based PNT

• 2007: President announces Selective Availability eliminated from future GPS III satellites

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U.S. Policy Promotes Global Use of GPS Technology

• No direct user fees for civil GPS services– Provided on a continuous, worldwide basis

• Open, public signal structures for all civil services– Promotes equal access for user equipment

manufacturing, applications development, and value-added services

– Encourages open, market-driven competition• Improve performance of civil GPS and

augmentations to meet or exceed that of international systems

• Encourage international development of PNT systems based on GPS

• Global compatibility and interoperability with GPS

• Protection of radionavigation spectrum from disruption and interference

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

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U.S. Space-Based PNT Organization Structure

WHITE HOUSEWHITE HOUSE

ADVISORY BOARD

Sponsor: NASA

ADVISORY BOARD

Sponsor: NASA

NATIONALEXECUTIVE COMMITTEEFOR SPACE-BASED PNT

Executive Steering Group

Co-Chairs: Defense, Transportation

NATIONALEXECUTIVE COMMITTEEFOR SPACE-BASED PNT

Executive Steering Group

Co-Chairs: Defense, Transportation

NATIONAL COORDINATION OFFICE

Host: Commerce

NATIONAL COORDINATION OFFICE

Host: Commerce

GPS International Working Group

Chair: State

GPS International Working Group

Chair: State

Engineering Forum

Co-Chairs: Defense, Transportation

Engineering Forum

Co-Chairs: Defense, Transportation

Ad HocWorking Groups

Ad HocWorking Groups

DefenseDefense

TransportationTransportation

StateState

InteriorInterior

AgricultureAgriculture

CommerceCommerce

Homeland SecurityHomeland Security

Joint Chiefs of StaffJoint Chiefs of Staff

NASANASA

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Executive Committee Activities

• Program Coordination– Five-Year National Plan– National PNT Architecture– GPS Modernization– Civil GPS Funding– Nationwide Differential

GPS– Enhanced LORAN– Distress Alerting Satellite

System

• International Cooperation– Bilateral– Multilateral

• Spectrum Management– Interference Detection

and Mitigation Plan– Spectrum Protection Plan

• Outreach– Publications, websites– Educational exhibit– Conferences, workshops,

other venues– Coordination of U.S.

message

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Overview

• Introduction• Global Positioning System• GPS Augmentations/Backups• U.S. Policy• International Cooperation

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International Cooperation

• Cooperative relationships established with Europe, Japan, Russia, India, Australia

• U.S. goals:– Compatibility and

interoperability– National security– Level playing field in global

markets

• Multilateral cooperation– International Committee on

GNSS– ICAO, IMO, NATO

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Planned GNSS

• Global Constellations– GPS (US)

– GLONASS (Russia)

– Galileo (EU)

– Compass (China)

• Regional Constellations– QZSS (Japan)

– IRNSS (India)

• Satellite-Based Augmentations– WAAS (US)

– MSAS (Japan)

– EGNOS (EU)

– GAGAN (India)

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Compatibility/Interoperability Objectives

• Ensure compatibility ― ability of U.S. and non-U.S. space based PNT services operating separately or together without interfering with each individual service or signal

– Radio frequency compatibility

– Spectral separation between M code and other signals

• Achieve interoperability – ability of civil U.S. and non-U.S. space-based PNT services operating together to provide better user capabilities than by relying on one service or signal

– Primary focus on the common L1C and L5 signalsPursue through Bi-lateral and Multi-lateral

CooperationPursue through Bi-lateral and Multi-lateral

Cooperation

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International Committee on GNSS

• Promotes GNSS use and integration into infrastructures, particularly in developing countries

• Encourages system compatibility, interoperability

• Membership: GNSS providers, international organizations and associations

• Providers Forum– United States, Europe, Russia, China, India,

Japan– Focused discussions on compatibility,

interoperability

• Next plenary in Pasadena, Dec 2008

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Summary

• GPS performance continues to improve– Augmentations enable even higher performance– New GPS signals are available now

– Modernization providing unprecedented new capabilities • U.S. policy encourages worldwide use of civil GPS

and augmentations• International cooperation is a high priority

– Actively engaged in multi-lateral/bi-lateral consultations

• As new GNSS systems and applications emerge, compatibility and interoperability are critical

• The U.S. goal is to maintain GPS as the recognized global “Gold Standard” – U.S. military PNT pre-eminence is a continuing priority

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For Additional Information…

GPS.gov PNT.gov

6822 Herbert C. Hoover BuildingWashington, D.C. 20230United States of America

Tel: +1 (202) 482-5809Email: Ken.Alexander@pnt.gov

Presentations and additional information:www.pnt.gov

BACKUPS

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L51176.45 MHz

E5a1176.45 MHz

E5b1207.14 MHz

L21227.6 MHz

E61278.75 MHz

L11575.42 MHz

L11575.42 MHz

1242.9375-1248.625 MHz

1598.0625-1605.375 MHz

GLONASSGLONASS

GALILEOGALILEO

L51176.45 MHz

L21227.6 MHz

LEX1278.75 MHz

L11575.42 MHz

QZSSQZSS

GPSGPS MMMMMMMMMMMM P(Y)P(Y)P(Y)P(Y)P(Y)P(Y)P(Y)P(Y)P(Y)P(Y)P(Y)P(Y)C/AC/AC/AC/A

MMMMMMMMMMMM P(Y)P(Y)P(Y)P(Y)P(Y)P(Y)P(Y)P(Y)P(Y)P(Y)P(Y)P(Y)C/AC/AC/AC/A

GNSS Frequency Bands and Signals

Possible futuresignal

L51176.45 MHz

L21227.6 MHz

E61278.75 MHz

L11575.42 MHz

Beidou/CompassBeidou/Compass

ITU Filings Here ITU Filings Here ITU Filings Here ITU Filings Here

Possible futuresignal

SBASSBAS

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Important for Interoperability

• Common Center Frequency– Like L5 & E5a

• Same Antenna Polarization• Common Signal Spectrum

– Identical receiver time delay with common spectrum

• Same coherent integration period for acquisition– Usually related to symbol rate– Different symbol rates may require separate

search correlators for acquiring signals

Essential (cost driver)

Desirable (ASIC gate count)

Important (no time bias or filter issues)

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GNSS integrity Channel (GIC)

Key Feature– Integrity

Determination External to User

• Key Enabler– Rapid Messaging Rate

– TTA of 6.2 Sec

• Key Benefit– Redundant Ranging

Signals Not Required

• Key Challenge– Meeting TTA

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Absolute RAIM

2

April 23, 2004

© 2004 The MITRE Corporation. All Rights Reserved.

Range Comparison Method (RCM) (Example with 5 SVs in View)

• Key Feature– Real-Time Integrity

Determination by the User (ABAS)

• Key Enabler– Redundant Ranging

Sources– 30 or More SVs

• Key Benefit– Latency Relaxed to

Hours

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Most recent monitored position withcorresponding horizontal protection level (HPL) and vertical protection level (VPL)

Propagate the most recent monitored position with carrier phase only

Growth in HPL and VPL due to RAIM on the carrier phase-based delta position updates

VPL

HPL

From Prof. van Graas, Ohio University

Relative RAIM: Range Rate Residuals

• Key Feature:– Real-Time Integrity

Determination By User Using Carrier Phase Approach

• Key Enabler– External Monitoring– Redundant

Geometry• Key Benefit

– TTA Latency Relaxed to Minutes

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WAAS Approach Procedures

LPVs: 1051 (as of 4/08)

LNAV/VNAVs: 1275WAAS Procedures to be Published to All Instrument Runways in the NAS by 2018

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Vertical Service Coverage

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WAAS RNP Coverage

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WAAS Avionics Status• Business & Regional Aircraft FMS Avionics

– Rockwell-Collins: Challenger (CL-604) STC Approval Expected in FY’08; CRJ-200 STC; Approval in Dec’08

– Canadian Marconi Corporation (CMC): WAAS Equipped Honeywell Primus 2000 FMS by Dec ‘08

– Universal Navigation Systems (UNS) Avionics: ~500 Dual Thread UNS-1 so far; Single Thread UNS-1 FMS LPV TSO; Approval Expected Sep 2008

• Air Carrier & Cargo Aircraft– Southwest Airlines: Equipping 200 Boeing 737 with

Rockwell Collins' GPS-4000S for RNP operations– Federal Express (FEDEX): Has equipped 253

Cessna Caravan aircraft with GNS-530W– Horizon Airlines: Has contracted to equip 48 Q400s

with UNS-1F• General Aviation

– Garmin: Over 33,000 WAAS Avionics Units– Bendix-King: & other suppliers bringing products to

market this year• Helicopter Aircraft Implementing WAAS

– Keystone & PHI Pursuing S-76/C++ LPV STC w/UNS-1Fwith Augusta-109 LPV STC Approval planned for Mar ‘09