Space-Based PNT Modernization Update David A. Turner National Space-Based PNT Coordination Office Presentation to the Munich Satellite Navigation Presentation to the Munich Satellite Navigation Summit Summit February 21-23, 2006 February 21-23, 2006 National Space-Based PNT Coordination Office
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Space-Based PNT Modernization Update David A. Turner National Space-Based PNT Coordination Office Presentation to the Munich Satellite Navigation Summit.
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Space-Based PNT Modernization Update
David A. TurnerNational Space-Based PNT
Coordination OfficePresentation to the Munich Satellite Navigation SummitPresentation to the Munich Satellite Navigation Summit
February 21-23, 2006February 21-23, 2006
National Space-Based PNTCoordination Office
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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
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• 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, 2005
• 2nd 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 93
29 Operating Satellites (to ensure 24)
GPS Constellation Status
Illustration reprinted courtesy of the GPS Joint Program Office
PDOP (Geometry) AvailabilitySpecification - PDOP of 6 or Less, 98% of the timeActual - 99.98798%
Horizontal Service AvailabilitySpecification - 95% Threshold of 36 meters, 99% of the TimeActual – 2.74 meters
Vertical Service AvailabilitySpecification - 95% Threshold of 77 meters, 99% of the Time or BetterActual – 3.89 meters
User Range ErrorSpecification - 6 meters or Less, Constellation AverageActual – see next chart
Specification values from the Standard Positioning ServicePerformance Standard, October, 2001
System accuracy and availability far exceedcurrent specifications
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4.64.3
3.02.7
2.11.8
1.51.22
0
1
2
3
4
5
6
7
1990 1992 1994 1996 1997 1999 2001 2005
Year
RM
S U
RE
(m
)
GPS User Range Error (URE) History
Actual Performance
As of July 2005
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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
• Frequency located in Aeronautical Radionavigation Services band (1164-1215MHz)
• Signal defined in IS-GPS-705
L5 code Begins with IIF sats24 Satellites: ~ 2015** Based on current schedule
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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
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Current GPS Monitoring Stations
USAF Sites – 6
Cape Canaveral
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Future GPS Monitoring Stations
Cape Canaveral
NGA Sites, AII – 6
NGA Sites, Non-AII -- 5
USAF Sites -- 6
Accuracy Improvement Initiative (AII)
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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
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• 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
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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
• 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
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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