Global Positioning System Modernization

1
Global Positioning SystemModernization

• CGSIC
• International Subcommittee Meeting
• s s s s s s s s s s s s s s s s

5 December, 2002
2
Overview

• Background
• Constellation Status/Performance
• Standard
• Modernization Program
• The Way Ahead

3
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

4
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

5
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

6
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

7
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

8
Overview

• Background
• Constellation Status/Performance
• Standard
• Modernization Program
• The Way Ahead

9
GPS Constellation Status
27 Operating Satellites (to ensure 24)

• 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

10
GPS Constellation Age
Block IIR MMD 12.67
Block IIR Predicted MMD
Block IIA Predicted MMD
Block IIA MMD 10.23
Block II MMD 9.6
Block II Predicted MMD
11
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
12
GPS SPS Performance Standard
13
Overview

• Background
• Constellation Status/Performance
• Standard
• Modernization Program
• The Way Ahead

14
GPS Modernization
Increasing System Capabilities Increasing
Defense/Civil Benefit
NAVWAR Capable Full Civil Rqmts Addl Capabilities
New Civil Signal L5
L2C on L2 M-Code (Earth)
Basic GPS
SA Set to 0
GPS III

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

GPS IIR-M, IIF
GPS IIA/IIR

• IIR-M Improved on all IIA capabilities and
  added
• 2nd Civil Signal on L2
• New L1 L2 M-Code
• IIF 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

Flex Power upgrade adds ability to increase power
on both P and M code signals to defeat low level
enemy jamming
15
Civil GPS Modernization

• 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

16
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
17
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
18
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

19
GPS Modernization Schedule
20
Overview

• Background
• Constellation Status/Performance
• Standard
• Modernization Program
• The Way Ahead

21
The Way Ahead (contd)

• 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
22
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
23
Global Positioning SystemModernization

• GPS Symposium
• Tokyo, Japan
• November 12, 2002
• s s s s s s s s s s s s s s s s
• Michael Shaw
• U.S. Department of Transportation

24
Backups
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GPS Augmentations

• 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

26
GPS Augmentations (contd)

• 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 operating system covering
the US coast to coast
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GPS Satellite Status
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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
28
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
29
GPS Position Error Daily Performance Global
Assessment, 2002
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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

31
GPS III Proposed Accuracy

• Draft Systems Specification

Threshold
Objective
Accuracy (95)
2.5 m
0.5 m
Horizontal
Vertical
1.1 m
4.5 m
Timing
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