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
Overview GPS Policy Objectives and Management System Improvements & Modernization Interoperability & International Collaboration NASA GPS Space Activities Summary 2
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 3
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 4
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 5
National Management of GPS Defense WHITE HOUSE Transportation State Commerce Homeland Security NATIONAL SPACE BASED PNT EXECUTIVE COMMITTEE Co Chairs: Defense, Transportation ADVISORY BOARD Sponsor: NASA NASA Joint Chiefs of Staff COORDINATION OFFICE Host: Commerce 6
Overview GPS Policy System Improvements & Modernization GPS Constellation Status Next Steps for Space and Control Segments Interoperability & International Collaboration NASA R&D Activities Summary 7
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 8
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 (1912 2003) 9
GPS Constellation Status as 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 10
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 11
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 12
Overview GPS Policy System Improvements & Modernization GPS Constellation Status Next Steps for Space and Control Segments Interoperability & International Collaboration NASA R&D Activities Summary 13
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 14
GPS Modernization Program Increasing System Capabilities Increasing Defense / Civil Benefit Block IIA/IIR Basic GPS Standard Service Single frequency (L1) Coarse acquisition (C/A) code navigation Precise Service Y Code (L1Y & L2Y) Y Code navigation Block IIR M, IIF 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 Block III Backward compatibility 4th civil signal (L1C) Increased accuracy Increased anti jam power Assured availability Increased security System survivability Search and Rescue 15
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 16
GPS Modernization Spectrum Power Spectrum (dbw/hz) Power Spectrum (dbw/hz) 220 230 240 250 220 230 240 250 previous as of Dec 2005 planned 1176.45 1176.45 L5 L5 Power Spectrum (dbw/hz) Power Spectrum (dbw/hz) 220 230 240 250 220 230 240 250 1227.6 1227.6 1227.6 Frequency (MHz) 1227.6 Frequency (MHz) P(Y) Frequency (MHz) L2C Frequency (MHz) 1575.42 1575.42 1575.42 1575.42 ARNS Band RNSS Band ARNS Band L2 M C/A L1 L1C Block IIA, 1990 Block IIR M, 2005 Block IIF, 2008 Block III, 2013 (artist s concept) 17
IIR 15(M) Launch & View From Space 25 September 2006 18
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 Block A Configuration Configuration Plus new capabilities demo Technology Development / Capability Insertion Program Plan 19
OCX Program Description IIR/M IIF III C2 Uplink and Downlink Monitor Stations Position, Velocity, Time Data Advanced Ground Antennas Battlespace Awareness Master Control Station (MCS) Advanced Ground Antenna Ground Antenna (GA) USAF Monitor Station (MS) National Geospatial Intelligence Agency (NGA) Tracking Station FAIRBANKS COLORADO SPRINGS ENGLAND USNO WASH D.C. VANDENBERG, AFB CAPE CANAVERAL HAWAII Master Control Station ASCENSION ECUADOR BAHRAIN DIEGO GARCIA SOUTH KOREA KWAJALEIN TAHITI Alternate Master Control Station (AMCS) ARGENTINA SOUTH AFRICA AUSTRALIA NEW ZEALAND The next generation GPS control segment (OCX) includes a new infrastructure with functionality that completes modernization capabilities. 20
Overview GPS Policy System Improvements & Modernization GPS Constellation Status Next Steps for Space and Control Segments Interoperability & International Collaboration GPS QZSS Progress NASA R&D Activities Summary 21
GPS/QZSS Agreement 27 January 2006 Unprecedented 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 22
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 % Time that at Least 1 of 3 QZSS Satellites Is Visible 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 23
Overview GPS Policy System Improvements & Modernization GPS Constellation Status Next Steps for Space and Control Segments Interoperability & International Collaboration GPS QZSS Progress NASA R&D Activities GPS to Earth Orbit, and Beyond Summary 24
GPS and Human Space Flight Miniaturized Airborne GPS Receiver (MAGR S) Modified DoD receiver to replace TACAN onboard 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 25
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 26
Augmentation of GPS in Space: GDGPS & TASS TDRS Augmentation Service for Satellites (TASS) provides Global Differential GPS (GDGPS) corrections via TDRSS satellites Integrates NASA s Ground and Space Infrastructures Provides user navigational data needed to locate the orbit and position of NASA user satellites 171 o W 47 o W ~18 20 o 85 o E 27
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 28
Navigation with GPS beyond Earth Orbit and on to the Moon GPS signals effective up to the Earth Moon 1 st 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 29
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 30
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 31