Global Positioning System Policy and Program Update

1
Global Positioning System Policy and Program
Update
Inaugural Forum Satellite Positioning Research
and Application Center Tokyo, Japan 23 April 2007

• James J. Miller, Senior GPS Technologist
• Space Communications and Navigation
• Space Operations Mission Directorate

2
Overview

• GPS Policy
• Objectives and Management
• System Improvements Modernization
• Interoperability International Collaboration
• NASA GPS Space Activities
• Summary

3
2004 U.S. PNT Policy Overview (GPS!)

• U.S. Space-Based Positioning, Navigation, and
  Timing (PNT) Policy
• Signed on 8 Dec 04 publicly released on 15 Dec
  04
• Updated U.S. policy while retaining prior GPS
  principles
• Established a stronger National Space-Based PNT
  Executive Committee IGEB disestablished
• Chaired by Deputy Secretaries of Defense and
  Transportation
• Created a new National Coordination Office
• Created a new Advisory Board from private sector
• Enabled new ways to fund future GPS modernization
  for civil applications

4
U.S. Policy Principles

• No direct user fees for civil GPS services
• Open public signal structure for all civil
  services
• Promotes equal access for user equipment
  manufacture, applications development and
  value-added services
• Facilitates open market driven competition
• Use of GPS time, geodesy, and signal standards
• Global compatibility and interoperability of
  future systems with GPS
• Protect the current radionavigation spectrum from
  disruption and interference
• Recognition of national and international
  security issues and protecting against misuse

5
New Policy Goals

• Provide uninterrupted availability of PNT
  services
• Meet growing demands in national, homeland,
  economic security, scientific, and commercial
  uses
• Continue to provide civil PNT services
• Ensure they exceed, or are at least equivalent
  to, those of foreign civil space-based PNT
  services
• U.S. space-based PNT services remain essential
  components of internationally accepted services

6
National Management of GPS
WHITE HOUSE
Defense
Transportation
NATIONALSPACE-BASED PNT EXECUTIVE
COMMITTEE Co-Chairs Defense, Transportation
State
ADVISORYBOARD Sponsor NASA
Commerce
Homeland Security
NASA
COORDINATIONOFFICE Host Commerce
Joint Chiefs of Staff
7
Overview

• GPS Policy
• System Improvements Modernization
• GPS Constellation Status
• Next Steps for Space and Control Segments
• Interoperability International Collaboration
• NASA RD Activities
• Summary

8
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 services
• Standard (free of direct user fees)
• Precise (U.S. and Allied military)
• Three segments
• Space
• Ground control
• User equipment

9
GPS is a Global Public Good

• GPS services are like a super lighthouse USG
  Owned Operated
• Paid for by U.S. taxpayers and provided free to
  the world
• Users are not hailed at port for fee or tax
  collection
• Managed at a national level as a multi-use asset
• Acquired and operated by Air Force on behalf of
  USG
• GPS receivers are like AM/FM radios
• Whenever, wherever -- without advertising!!
• Adding users costs nothing
• Tracking its usage is impossible through GPS
  itself
• GPS is not a fee-for-service utility like cable
  TV
• Usage is not metered -- direct cost to user is
  zero
• Civil access is open and unconstrained by locks
  or encryption
• Public domain documentation
• Available on an equal basis to users and industry
  worldwide
• Anyone can develop user equipment

Lighthouses in the sky, serving all mankind Dr.
Ivan A. Getting (19122003)
10
GPS Constellation Statusas of 12 Feb 07
30 Healthy Satellites Baseline Constellation 24

• 15 Block IIA satellites operational
• 12 Block IIR satellites operational
• 3 Block IIR-M satellites operational
• 5 additional IIR-M satellites to launch
• Since Dec 93, U.S. Government met/exceeded civil
  GPS service performance commitments
• SPS Performance Standard (PS)
• U.S. DoD committed to superior GPS service

11
GPS Monitoring Stations
Cape Canaveral
Original USAF Sites - 6 NGA sites transmitting to
OCS since Aug 2005 - 6 NGA sites transmitting to
OCS since Dec 2006 - 5
12
GPS Single Frequency Performance
Steady decrease in error due to improvements such
as the addition of new monitoring stations,
tighter control of clocks, etc.
System accuracy far exceeds current standard
13
Overview

• GPS Policy
• System Improvements Modernization
• GPS Constellation Status
• Next Steps for Space and Control Segments
• Interoperability International Collaboration
• NASA RD Activities
• Summary

14
GPS Modernization Goals

• System-wide improvements in
• Accuracy
• Availability
• Integrity
• Reliability
• Robustness against interference
• Improved indoor, mobile, and urban use
• Interoperability with other GNSS constellations
• Backward compatibility

15
GPS Modernization Program
Increasing System Capabilities w Increasing
Defense / Civil Benefit
Block IIA/IIR
Block III
Block IIR-M, IIF

• Backward compatibility
• 4th civil signal (L1C)
• Increased accuracy
• Increased anti-jam power
• Assured availability
• Increased security
• System survivability
• Search and Rescue

• 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

16
Modernized GPS Civil Signals

• Second civil signal (L2C)
• Designed to meet commercial needs
• Higher accuracy through ionospheric correction
• Higher effective power and improved data
  structure reduce interference, speed up signal
  acquisition, enable miniaturization of receivers,
  may enable indoor use
• 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)
• Uses highly protected Aeronautical Radio
  Navigation Service (ARNS) band
• Begins with GPS Block IIF
• First launch 2008 24 satellites 2016
• Fourth civil signal (L1C)
• Designed with international partners to enable
  GNSS interoperability
• Begins with GPS Block III
• First launch 2013 24 satellites 2021

17
GPS Modernization Spectrum
Block IIA, 1990
previous
as of Dec 2005
Block IIR-M, 2005
planned
Block IIF, 2008
Block III, 2013
(artists concept)
ARNS Band RNSS Band
ARNS Band
18
IIR-15(M) Launch View From Space 25 September
2006
19
GPS III Acquisition Approach
Increment IIIA

• Block A Configuration
• New L1C Signal
• New GPS III SV Platform

Plus demo high-speed communication (uplink,
downlink crosslink)
Increment IIIB
Block A Configuration
Plus new capabilities demo
Increment IIIC
Block A Configuration
Block A Configuration
Plus new capabilities demo
Technology Development / Capability Insertion
Program Plan
20
OCX Program Description
IIF
III
IIR/M
Position, Velocity, Time Data
C2 Uplink and Downlink
MonitorStations
Advanced Ground Antennas
Battlespace Awareness
AUSTRALIA
The next generation GPS control segment (OCX)
includes a new infrastructure with functionality
that completes modernization capabilities.
21
Overview

• GPS Policy
• System Improvements Modernization
• GPS Constellation Status
• Next Steps for Space and Control Segments
• Interoperability International Collaboration
• GPS-QZSS Progress
• NASA RD Activities
• Summary

22
GPS/QZSS Agreement 27 January
2006Unprecedented Compatibility
Interoperability

• QZSS designed to work with enhance civil
  services of GPS
• Availability enhancement
• Performance enhancement
• GPS QZSS have established that their signals
  are RF compatible

23
GPS-QZSS Technical Working Group (TWG)

• Civil system for Asia-Pacific region
• Enhances civil GPS services
• First QZSS launch expected in 2009
• GPS-QZSS technical meetings
• Nov 04 in Washington, DC, US
• July 05 in Hawaii, US
• January 06 in Tokyo, Japan
• Aug 06 in Hawaii
• Next mtg. in Washington, DC, in May
• GPS QZSS success in designing common signals
• Five of six QZSS signals use same signal
  structures, frequencies, spreading code
  families, data message formats as GPS or SBAS
  signals
• Draft interface specification (IS) for QZSS
  released in January 2007
• IS-GPS-200, IS-GPS-705, IS-GPS-800 are baseline
  documents

Time that at Least 1 of 3 QZSS Satellites Is
Visible
24
Overview

• GPS Policy
• System Improvements Modernization
• GPS Constellation Status
• Next Steps for Space and Control Segments
• Interoperability International Collaboration
• GPS-QZSS Progress
• NASA RD Activities
• GPS to Earth Orbit, and Beyond
• Summary

25
GPS and Human Space Flight

• Miniaturized Airborne GPS Receiver
• (MAGR-S)
• Modified DoD receiver to replace TACAN on-board
  the Space Shuttle
• Designed to accept inertial aiding and capable of
  using PPS
• Single-string system (retaining three-string
  TACAN) installed on OV-103 Discovery and OV-104
  Atlantis, three-string system installed on OV-105
  Endeavour (TACAN removed)
• GPS taken to navigation for the first time on
  STS-115 / OV-104 Atlantis

STS-115 Landing

• Space Integrated INS/GPS (SIGI)
• Receiver tested on shuttle flights prior to
  deployment on International Space Station (ISS)
• The ISS has an array of 4 antennas on the T1
  truss assembly for orbit and attitude
  determination

26
Navigation with GPS Space-Based Range

• Space-based navigation, GPS, and Space Based
  Range Safety technologies are key components of
  the next generation launch and test range
  architecture
• Provides a more cost-effective launch and range
  safety infrastructure while augmenting range
  flexibility, safety, and operability
• Memorandum signed in November 2006 for GPS Metric
  Tracking (GPS MT) by January 1, 2011 for all DoD,
  NASA, and commercial vehicles launched at the
  Eastern and Western ranges

GPS-TDRSS Space-Based Range
27
Augmentation of GPS in Space GDGPS TASS

• TDRS Augmentation Service for Satellites (TASS)
  provides Global Differential GPS (GDGPS)
  corrections via TDRSS satellites
• Integrates NASAs Ground and Space
  Infrastructures
• Provides user navigational data needed to locate
  the orbit and position of NASA user satellites

28
Navigation with GPS beyond LEO

• GPS Terrestrial Service Volume
• Up to 3000 km altitude
• Many current applications
• GPS Space Service Volume (SSV)
• 3000 km altitude to GEO
• Many emerging space users
• Geostationary Satellites
• High Earth Orbits (Apogee above GEO altitude)
• SSV users share unique GPS signal challenges
• Signal availability becomes more limited
• GPS first side lobe signals are important
• Robust GPS signals in the Space Service Volume
  needed
• NASA GPS Navigator Receiver in development

29
Navigation with GPS beyond Earth Orbit and on
to the Moon

• GPS signals effective up to the Earth-Moon 1st
  Lagrange Point (L1)
• 322,000 km from Earth
• Approximately 4/5 the distance to the Moon
• GPS signals can be tracked to the surface of the
  Moon, but not usable with current GPS receiver
  technology

30
Earth-Moon Communications and Navigation
Architecture

• Options for Communications and/or Navigation
• Earth-based tracking, GPS, Lunar-orbiting
  communication and navigation satellites with
  GPS-like signals, Lunar surface beacons and/or
  Pseudolites
• The objective is integrated interplanetary
  communications, time dissemination, and
  navigation

31
Summary

• Continuing success in GPS sustainment
  modernization
• New capabilities delivering enhanced performance
• Developments on track to enhance space and
  control segments
• Civilian use of GPS, and GPS-derived systems, is
  already extending well beyond Earth
• International participation will make new
  worldwide GPS applications grow more robust and
  valuable for generations to come