Space-Based PNT Modernization Update David A. Turner National Space-Based PNT Coordination Office Presentation to the Munich Satellite Navigation Summit February 21-23, 2006 National Space-Based PNT Coordination Office

2 OVERVIEW Background GPS Status & Modernization Augmentations Status Summary

Background GPS Status & Modernization Augmentations Status Summary

4 GPS Background Active program for over 30 years –Created from separate programs in 1973 –Developmental satellites began launch in 1978; operational satellites in 1989 –Initial Operational Capability in 1993; Full Operational Capability in 1995 Developed as a dual-use system –Military applications for US and Allied use –Civilian applications for worldwide use Consistent U.S. National Policy from both Executive and Legislative branches –Presidential Decision Directive - March 1996 captured by U.S. Public Law - December 1997 –U.S. Space-Based Positioning, Navigation, and Timing (PNT) Policy, December 2004

5 Dr. Getting Plaque

GPS Status & Modernization Background Augmentations Status Summary

7 16 Block II/IIA satellites operational 12 Block IIR satellites operational –Modernizing up to 8 Block IIR satellites 1 Block IIR-M in orbit (launched Sep 25) –Set healthy on December 16, nd IIR-M launch currently being scheduled –No earlier than May 25, 2006 Continuously assessing constellation health to determine launch need Global GPS civil service performance commitment met continuously since Dec Operating Satellites (to ensure 24) GPS Constellation Status Illustration reprinted courtesy of the GPS Joint Program Office

8 Constellation Performance January 1-December 31, 2004 PDOP (Geometry) Availability Specification - PDOP of 6 or Less, 98% of the time Actual % Horizontal Service Availability Specification - 95% Threshold of 36 meters, 99% of the Time Actual – 2.74 meters Vertical Service Availability Specification - 95% Threshold of 77 meters, 99% of the Time or Better Actual – 3.89 meters User Range Error Specification - 6 meters or Less, Constellation Average Actual – see next chart Specification values from the Standard Positioning Service Performance Standard, October, 2001 System accuracy and availability far exceed current specifications

9 GPS User Range Error (URE) History Actual Performance As of July 2005

10 Why Modernize? For civil users, new signals provide: –More robustness against interference –Compensation for ionospheric delays –Wide-laning/tri-laning -- Resolves integer ambiguities caused by cycle slips during precise carrier phase measurements For military users, new spectrally separated signals provide: –Protection of friendly use –Prevention of adversary exploitation –Preservation of civil use outside area of operations For both civil/military, system improvements in accuracy, availability, integrity, and reliability

11 GPS Modernization The GPS Modernization Path 14 Source: GPS Joint Program Office

12 Second Civil Signal (L2C) Improves service for ~ 50,000 current scientific/ commercial dual-frequency users Will enable higher civilian accuracy when combined with existing civil GPS signal (L1 C/A) Overcomes some limitations of L1 C/A –Higher effective power and improved data structure will reduce interference and may enable better indoor use –Can be broadcast from an almost unlimited number of satellites Signal defined in IS-GPS-200D L2C code Begins with IIR-M sats 24 Satellites: ~ 2012* * Based on current schedule

13 Third Civil Signal (L5) New signal structure for enhanced performance Higher power than other GPS civil signals –Higher power (no less than dBW) –Wider bandwidth ( MHz +/- 10 MHz) – Improves resistance to interference Frequency located in Aeronautical Radionavigation Services band ( MHz ) Signal defined in IS-GPS-705 L5 code Begins with IIF sats 24 Satellites: ~ 2015* * Based on current schedule

14 Ground Control Modernization New Master Control Station with: –Improved operator interfaces –IIR-M and IIF capabilities –Integrated Mission Operations Support Center –Launch and Early Orbit Anomaly Resolution and Disposal Operations (LADO) Fully mission capable Alternate Master Control Station Legacy Accuracy Improvement Initiative – Additional information from National Geospatial-Intelligence Agency sites: – Doubles amount of data being used for signal integrity and constellation performance monitoring – Doubles amount of data used for satellite time and position estimation, resulting in more accurate satellite orbital position and clock data available to users

15 Current GPS Monitoring Stations USAF Sites – 6 Cape Canaveral

16 Future GPS Monitoring Stations Cape Canaveral NGA Sites, AII – 6 NGA Sites, Non-AII -- 5 USAF Sites -- 6 Accuracy Improvement Initiative (AII)

17 GPS III Goals Increased system accuracy Assured and improved level of unaugmented integrity –Compliments other sources (SBAS, RAIM) Improved availability of accuracy with integrity Backward compatibility with existing receivers Support for new signals in combination with IIR-M & IIF satellites –L2C, L5, M-code (existing with IIR-M, IIF) –L1C and future options for new navigation messages, flexible power levels Smooth transition from GPS Block II to Block III

18 Government & Industry have completed studies of combined civil & military architectures Systems Requirements Reviews completed in summer 2005 Separate space segment and control segment contracts will be awarded for the design phase of the program GPS III Capability Development Document (CDD) was reviewed by the Interagency Forum for Operational Requirements and approved by the Joint Requirements Oversight Council (JROC) in August 05 GPS III Status

19 L1C Signal Modernized L1 civil signal –In addition to C/A code to ensure backward compatibility –Binary Offset Carrier [BOC] (1,1) modulation Increased robustness and potentially accuracy for civil users Proposed as a common baseline L1 open service signal for GPS & Galileo L1C Begins with GPS III sats First launch: ~ 2013* For additional information contact: * Based on current schedule

20 GPS Modernization Schedule

Augmentations Status Background GPS Status & Modernization Summary

22 Wide Area Augmentation System (WAAS) WAAS consists of: –25 Reference Stations More being added in Canada/Mexico –2 Master Stations –2 Geosynchronous Satellites –3 Uplink Stations WAAS augments GPS to meet the integrity, availability, accuracy, and continuity for use in all phases of flight GPS/WAAS - primary navigation system in US national airspace –WAAS Commissioned in July 2003 –En-route through approach Allows reduction in ground-based navigation aids Interoperable with European EGNOS Japanese MSAS, and Indian GAGAN Illustration reprinted courtesy of the U.S. Department of Transportation

23 Nationwide Differential GPS System (NDGPS) Designed to an international, non-proprietary standard compliant with RTCM and ITU with f requencies optimum for surface transportation 50 countries operate compatible systems resulting in a seamless international navigation system

24 Continuously Operating Reference Stations (CORS) Network A cooperative endeavor involving more than 130 government, academic, and private organizations –Administered by the National Geodetic Survey of the National Oceanic and Atmospheric Administration Provides accurate, 3-dimensional, post-mission positioning ties to National Spatial Reference System –Uses include land management, coastal monitoring, civil engineering, boundary determination, mapping, geographical information systems, and future improvements to weather prediction and climate monitoring CORS Network contained 850+ sites as of Oct 2004 –Growing at rate of 8 sites per month –Includes all existing NDGPS/DGPS sites and FAA WAAS sites

25 International GPS/GNSS Service Network of over 350+ stations throughout the globe –Precision geodetic receivers produce GPS data on a continuous basis, ~ 35 also track GLONASS Over 200 contributing organizations throughout 80 countries to include the U.S. and India –A service of the International Association of Geodesy (IAG) since January 1, 1994 Advocates an open data policy, equal access Highest accuracy GPS & GLONASS satellite orbits anywhere –3-5 cm GPS, ~25-30cm GLONASS –mm-level station positions and velocities IGS Central Bureau at NASA/Jet Propulsion Lab responsible for day-to-day management and coordination –Global Data Center at NASA Goddard Space Flight Center

Summary Background GPS Status & Modernization Augmentations Status

27 Summary GPS is rapidly evolving into a key part of the global infrastructure Civil service continues to exceed performance standards Next step in Modernization has begun –IIR-M launch with L2C and M-code –Enhancements will continue through GPS III Augmentations continue to be an integral component of U.S. Space-Based PNT Services Continuously Improving GPS & Augmentation Services are benefiting users worldwide

National Space-Based PNT Coordination Office Herbert C. Hoover Building, Rm th & Constitution Ave., NW Washington, D.C Phone: Fax: