global positioning system modernization cgsic international subcommittee meeting 5 december, 2002

Global Positioning SystemModernization

CGSIC International Subcommittee Meeting

5 December, 2002

ISC, Brussels, 5 December 2002 2

Overview

• Background

• Constellation Status/Performance Standard

• Modernization Program

• The Way Ahead


GPS Background

• Active program for over 25 years• Created from separate programs in 1973• Developmental satellites began launch in 1978

• Operational satellites began launch in 1989• Initial Operational Capability - 1993• Full Operational Capability –1995

• Open civil navigation service• Signal specification available to industry and all users, both US and International• Free of direct user fees


GPS Satellites

Block IIF• In development• Boeing• 6 already procured• Options for 6 more• MMD 11.35 yrs

Block IIR/IIR-M• In production• Lockheed/Martin• 21 procured• 6 operational• 1 destroyed on launch• MMD 10.62/8.57 yrs

Block II/IIA• All have been launched• Rockwell (now Boeing)• First launch Feb 1989• 21 operational• Mean Mission Duration (MMD) 9.6/10.23 yrs


US Policy Goals

• Encourage acceptance of GPS into peaceful civil, commercial and scientific applications

• Promote safety and efficiency in transportation

• Encourage private investment in/use of GPS

• Strengthen and maintain national security• Promote international cooperation in using

GPS for peaceful purposes


US Policy Principles

• No direct user fees • Open market competition for user equipment• Equal access for applications development and

value added services• Common use of GPS time, geodesy, and signal

structure standards• Interoperability of future systems with GPS• Recognition of security issues and protecting

against misuse• Protect radionavigation spectrum from

disruption and interference


GPS Civil Applications

• Enabling Technology• Unlimited growth potential• $16 Billion industry worldwide by year 2003

• Japan projected to have 44% of customer market share

• Expanding Use in Transportation Safety• Aviation, Maritime, Railroad, Highway, etc• Potential to reduce land-based navigation systems

• Wide Range of Other Civil Uses• Telecommunications, Surveying, Law Enforcement,

Emergency Response, Agriculture, Mining, etc.• Distress Alerting Satellite System (DASS), civil

component of Global Personnel Recovery System


Overview

• Background



• The Way Ahead


• 21 Block II/IIA satellites operational

• 6 Block IIR satellites operational• 14 of 21 Block IIR satellites available• Modernizing up to 8 Block IIR satellites• Last launch: 31 Jan 01

• Next Launch: On hold• Launch vehicle issues

• Continuously assessing constellation health to determine launch need

27 Operating Satellites (to ensure 24)

GPS Constellation Status


GPS Constellation Age

Block II MMD = 9.6Block IIA MMD =10.23

Block IIR MMD = 12.67

0

2

4

6

8

10

12

14

14 13 16 19 17 18 20 21 15 23 24 25 28 26 27 32 29 22 31 37 39 35 34 36 33 40 30 38 43 46 51 44 41 54

II-1 II-2 II-3 II-4 II-5 II-6 II-7 II-8 II-9 II-10

II-11

II-12

II-13

II-14

II-15

II-16

II-17

II-18

II-19

II-20

II-21

II-22

II-23

II-24

II-25

II-26

II-27

II-28

IIR-2

IIR-3

IIR-4

IIR-5

IIR-6

IIR-7

E1 B3 E5 A4 D3 F3 B5 E2 D5 E4 D1 A2 C5 F2 A3 F1 F4 B1 C3 C4 A1 B4 D4 C1 C2 E3 B2 A5 F3 D2 E1 B5 F1 E3

YE

AR

S

SVNMissionSlot

Block IIA Predicted MMD

Block II Predicted MMD

Block IIR Predicted MMD


GPS SPS Performance Standard

• Defines the levels of performance the U.S. Government commits to provide to domestic and international civil GPS users

• Not a requirements document• Current edition published October 2001

• Updated performance as a result of discontinuing Selective Availability

• Available on US Coast Guard Navigation Center website• http://www.navcen.uscg.gov/

A Commitment of Service


GPS Performance Standard Metric

2nd Edition SPS Signal Specification

June 1995

SPS Performance Standard October 2001

Representative Performance (12

month period)

Global Accuracy All-in-View Horizontal 95%

All-in-View Vertical 95%

100 meters 156 meters

13 meters 22 meters

4 meters 6 meters

Worst Site Accuracy All-in-View Horizontal 95%

All-in-View Vertical 95%

100 meters 156 meters

36 meters 77 meters

6 meters 10 meters

Time Transfer Accuracy All-in-View Time Transfer

User Solution 95%

340 nanoseconds

40 nanoseconds

7-10 nanoseconds

Constellation RMS User Range Error

NONE 6 meters 1.6 meters

Geometry (PDOP 6) 95.87% global 83.92% site

98% global 88% site

99.9% global 98% site

Constellation Availability NONE 95% Probability of 24 Operational Satellites

25-28 Healthy Satellites

Service Reliability

Service Failure Threshold

Service Failure Rate

Service Failure Duration

99.97% global 99.79% worst site

500 m Horizontal Error

3/Year

Up to 6 Hours/Failure

99.94% global 99.79% worst site

30 m SIS URE

3/Year

Up to 6 Hours/Failure

100% global 100% worst site (28 July 2001 PRN22 Failure

almost 2 hours of URE > 30 m

GPS SPS Performance Standard


Overview

• Background



• The Way Ahead


GPS IIA/IIR

GPS III

GPS IIR-M, IIFIIR-M: Improved on all IIA capabilities

and added• 2nd Civil Signal on L2• New L1 & L2 M-CodeIIF: IIR-M capability and:• Add 3rd Civil Signal on L5

• Standard Service (~100 m)• Precise Service (~16 m)• Two Nav frequencies L1: Civil (C/A) & Precise code, Navigation L-2: P-code Nav

GPS-III:• Navigation Surety• Increased Accuracy• Assured Availability• Controlled Integrity• System Survivability Other Transformational needs • Nav-related Messaging• Navigation Operations• Adjunct to BFT

Basic GPS

L2C on L2M-Code (Earth)

NAVWAR CapableFull Civil Rqmts

Add’l Capabilities

New Civil Signal – L5

GPS ModernizationIncreasing System

CapabilitiesIncreasing Defense/Civil

Benefit

SA Setto 0

Flex Power upgrade adds ability to increase power on both P and M code signals to defeat low level enemy jamming


• Setting SA to zero considered first step• Civil users currently limited to one GPS signal

• C/A code at L1 frequency (1575.42 MHz)• Low power signal, not intended for precision nav• C/A = “Coarse Acquisition”; P = “Precise”

• Adding a second civil signal• C/A-type code at L2 frequency (1227.60 MHz)• Low power signal, not intended for precision nav

• Adding a third civil signal• P-type codes at L5 frequency (1176.45 MHz)• Higher power signal, intended for precision nav

Civil GPS Modernization


Second Civil Signal (L2C)• More robust civil signal service

• Civil users currently only have codeless/semi-codeless access to P(Y) on L2

• Increased accuracy• Coded dual-frequency ionospheric corrections at the receiver

• Advanced signal structure • Working Group defined signal characteristics• Better cross-correlation properties than C/A• Data-free component for robust tracking• Designated as primary L2 civil code versus C/A

Begin Launch in 2004; Projected for Full

Capability in 2012


Third Civil Signal (L5)• Improved signal structure for enhanced performance

• ~ 6 dB higher power relative to L1• Broadcast over the full registered 24 MHz band

• Spectrum allocated for aeronautical radionavigation services (ARNS) (960 – 1215 MHz)• Co-primary allocation for RNSS received at the last

World Radio Conference (1164 – 1215 MHz)

• DME compatibility achieved by frequency reallocation, if required

• L5 signal definition• RTCA SC 159, WG #1, developed L5 Specification • GPS JPO originated/coordinated ICD-GPS-705

Begin Launch in 2005; Projected Full Capability in 2015


Civil Benefits of GPS Modernization

• More robust GPS service• Reduces vulnerability to unintentional interference • Unlikely to simultaneously affect L1, L2 and L5

• Worldwide dual frequency for en-route navigation and precision approach• Dual Frequency (L1, L5) allows ionospheric corrections

in avionics onboard the aircraft

• Fewer reference stations may be needed for space-based augmentation systems (e.g. WAAS)

• Centimeter-level accuracy for scientific & survey applications


GPS Modernization Schedule

Activity

Implementation Date

SA set to zero

May 2000

GPS IIR-M Enhancements (Up to 8 satellites)

New L2 Civil (L2C) Signal M-code on L1 & L2

2004 – 2006

GPS IIF Enhancements (Up to 12 satellites)

New L2 Civil (L2C) Signal M-code on L1 & L2 L5

2005 – 2011

GPS III Enhancements New L2 Civil (L2C) Signal M-code on L1 & L2 L5 Future Capabilities

2011 – TBD

OCS Enhancements 2000 – 2008


Overview

• Background



• The Way Ahead


The Way Ahead (cont’d)

• Future of global satellite navigation services is bright

• Compatibility/interoperability is critical between GPS and future systems• European Galileo• Japanese Quasi-Zenith

Seamless, global interoperability of future systems with GPS is in best interest of all

navigation users


Summary• Stable, consistent GPS policy and service• Expanding use in transportation safety • GPS Modernization is a multiple step process

• Second civil signal (L2C) beginning in 2004• Third civil signal (L5) beginning in 2005• GPS III addressing future dual-use requirements

• Continuing international outreach to be responsive to global user needs

• Compatibility/interoperability with other future systems is critical

Future GPS performance will dramatically improve as a result of modernization

Global Positioning SystemModernization

GPS SymposiumTokyo, Japan

November 12, 2002

Michael ShawU.S. Department of Transportation


Backups


• Wide Area Augmentation System (WAAS)• Enroute thru near precision approach • Signal in space currently available

• Use at your own risk until operational (2003)

• Commissioning for aviation use by late 2003• Allows reduction in ground-based nav aids

• Local Area Augmentation System (LAAS)• Terminal through CAT III Precision Approach• Research and development program

GPS Augmentations


GPS Augmentations (cont’d)

• Maritime Differential GPS (MDGPS) System• Accuracy better than 10 meters• Currently 40 nations implementing Maritime DGPS

• Nationwide Differential GPS (NDGPS) System• Expanding MDGPS to cover entire U.S.• Positive Train Control for railroads• Intelligent Transportation Systems for highway use• 23 stations currently operating• Full operational capability by end of 2007

MDGPS and NDGPS are one operatingsystem covering the US coast to coast


SVN 23

SVN 21yr

GPS Satellite Status

Bottom Line

16 vehicles are “yellow” (i.e. single string)

9 vehicles are yellow due to bus failures

13 vehicles are yellow due to nav failures

SVN 25

SVN 27

SVN 38

SVN 39 SVN 22

SVN 30

SVN 44

SVN 35

SVN 13

SVN 36

SVN 33

SVN 31

SVN 37

SVN 24

SVN 46

SVN 17

SVN 34

SVN 15

SVN 51

SVN 40

SVN 54

SVN 41

SVN 26

SVN 43

SVN 32

SVN 29

SVNLEGEND

y g

D

1

2

3

4

5

FA B C E

BU

S

NA

V

g g

g

g g

g

g

g g

g g

g g

g g

g

g

g

g g

g g

g y

g g

g

g g

g g

g

y

y

y y

y

y y

y

y y

y y

y

y

y y

y y

y

yy


Constellation Summary

• Age Summary• 7 satellites past updated mean mission

duration

• Health Summary • 13 Satellites one component away from

navigation mission failure• 9 satellites one component away from bus failure

Despite age and component issues, all satellites are providing a healthy nav signal


GPS Position Error Daily Performance –

Global Assessment, 2002


Key GPS III Goals for Civil Signals

• Significant increase in system accuracy• Assured and improved level of unaugmented

integrity• Improved availability of accuracy with integrity• Backward compatibility with existing receivers• IOC for L5 (in combination with IIF satellites)• Smooth transition from GPS Block II to Block III• Flexibility to respond to evolving requirements with limited programmatic impacts


GPS III Proposed Accuracy

Draft Systems SpecificationThreshold Objective

Accuracy (95%)

Horizontal

Vertical

Timing

2.5 m 0.5 m

4.5 m 1.1 m

5.7 nsec 1.3 nsec

Includes the effects of receivers• Threshold is for low-cost/low-performance receiver• Objective is for high-cost/high-performance receiver

global positioning system modernization cgsic international subcommittee meeting 5 december, 2002

Documents