Space-Based PNT Modernization Update

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Space-Based PNT Modernization Update
National Space-Based PNT Coordination Office

• David A. Turner
• National Space-Based PNT Coordination Office

Presentation to the Munich Satellite Navigation
Summit February 21-23, 2006
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OVERVIEW

• Background
• GPS Status Modernization
• Augmentations Status
• Summary

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Background

• GPS Status
• Modernization
• Augmentations Status
• Summary

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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

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Dr. Getting Plaque
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GPS Status Modernization

• Background
• Augmentations Status
• Summary

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GPS Constellation Status
29 Operating Satellites (to ensure 24)

• 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

Illustration reprinted courtesy of the GPS Joint
Program Office
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Constellation PerformanceJanuary 1-December 31,
2004
Specification values from the Standard
Positioning Service Performance Standard,
October, 2001
PDOP (Geometry) Availability Specification - PDOP
of 6 or Less, 98 of the time Actual -
99.98798 Horizontal Service Availability Specific
ation - 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
System accuracy and availability far
exceed current specifications
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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

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The GPS Modernization Path
GPS Modernization
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Source GPS Joint Program Office
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Second Civil Signal (L2C)
Begins with IIR-M sats 24 Satellites 2012
Based on current schedule

• 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

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Third Civil Signal (L5)
Begins with IIF sats 24 Satellites 2015
L5 code
Based on current schedule

• New signal structure for enhanced performance
• Higher power than other GPS civil signals
• Higher power (no less than -154.9 dBW)
• Wider bandwidth (1176.45 MHz /- 10 MHz)
• Improves resistance to interference
• Frequency located in Aeronautical Radionavigation
  Services band (1164-1215MHz)
• Signal defined in IS-GPS-705

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

• 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

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L1C Signal
Begins with GPS III sats First launch 2013
L1C
Based on current schedule

• 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

For additional information contact
L1C_GPS_at_USGS.gov
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GPS Modernization Schedule
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Augmentations Status

• Background
• GPS Status
• Modernization
• Summary

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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

Illustration reprinted courtesy of the U.S.
Department of Transportation

• 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

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Nationwide Differential GPS System (NDGPS)

• Designed to an international, non-proprietary
  standard compliant with RTCM and ITU with
  frequencies optimum for surface transportation
• 50 countries operate compatible systems resulting
  in a seamless international navigation system

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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

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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 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

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Summary

• Background
• GPS Status
• Modernization
• Augmentations Status

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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
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National Space-Based PNT Coordination
OfficeHerbert C. Hoover Building, Rm. 682214th
Constitution Ave., NWWashington, D.C.
20230Phone [phone]Fax
001.202.482.4429PNT.Office_at_pnt.govhttp//pnt.gov
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