Docstoc

HA-NDGPS

Document Sample
HA-NDGPS Powered By Docstoc
					     High Accuracy
 Nationwide Differential
Global Positioning System
      (HA-NDGPS)


     Jim Arnold
  CGSIC New Orleans
      July 2008
Problem and Program Objectives
         HA-NDGPS
Problem: Submeter resolution of vehicle position needed
for many advanced vehicle safety concepts.
Program Objective: Assess the implementation feasibility
for improving the accuracy of the NDGPS service, using
existing infrastructure, to meet the requirements of additional
applications without decreasing availability and integrity
and still meeting the needs of existing users.
• Examine ways to enable 3-D dynamic positioning at
   the centimeter level throughout the US,
• Coexist with existing infrastructure,
• Minimize deployment costs.
   Perspective on Accuracy
   Horizontal, Dynamic, 95%



HA-NDGPS(Dynamic)   HA-NDGPS(Static)
(.1 Meters)         (.01 Meters)


                    NDGPS
                    (1-2 meters)

                                   GPS
                                   (13 meters)
                     NDGPS
• Nationwide network of GPS reference
  stations
• Provide real time code phase corrections for
  diverse applications
  – Transportation
  – Agriculture
  – GIS
• Provides data for other users
  – NGS
  – UNAVCO
  – Etc.
Coverage
BUPG
       The Site



       Electronics



                     ATU

GSOS
HA-NDGPS Program Phases
• Phase 1
     Develop Modulator and Data Link Receivers
     Interface System Modules
     Broadcast Characterization and Optimization
     Single Site Concept Demonstration (Hagerstown, MD)


• Phase 2
     Pre-Broadcast Integrity Algorithm
     Multiple Site/Baseline Concept Demonstration (Hawk
      Run, PA)
     Iono/Tropo Prediction
     Application Development
               Broadcast Site
               Configuration
            OBSERVABLES          DATA
REFERENCE                                             MODULATOR
                           FORMATTER
 STATION    CORRECTIONS                                   DSP/Analog Card


                                          Rack Mount PC




                                  DGPS/NDGPS
                   TRANSMITTER


                                                    DIPLEXER                TO ANTENNA


                   TRANSMITTER
                                  HIGH ACCURACY
                                  DGPS
Data Formatter/Modulator   Diplexor
Static Positioning at 50 km
         Actual Real-time Hydra plot of static
             geodetic survey application
            performed at Dickerson, MD
           47.8 km from reference station.

             Reference Data Source –
         Hagerstown HA-NDGPS Broadcast
Long Range Single Baseline
          Test
      Tangier Island HA-NDGPS Experiment
      (250 km). Comparison of approximate
      “truth” geodetic coordinates of mail boat
      With the real-time solution based upon
      the HA-NDGPS broadcast. Results are
      roughly 10-20 centimeters as expected
      at this great range.
                               Phase II
• Hawk Run Installation Status
  – Installed and Operating
• Testing
  – Report available
     • http://www.navcen.uscg.gov/ndgps/HA-NDGPS.PhaseII.Report.July2004.four.pdf

• Application Development
  – Partnering with other agencies to develop applications
  – US Army Corps of Engineers
HA-NDGPS Coverage




                Orbisonia , PA
                50 mile baselines

               Hagerstown, MD
               Hawk Run, PA
Multi-Station
              “Accurate” Solution
               Nationwide RTK?
• What You Need:                   • What You Get:
   – Satellite Lock                   – Initial .5 to 2 meter code
   – Ground based system                accuracy
     broadcasting observables         – Reduced search space for
   – Accurate Ephemeris                 integers
   – Accurate Clock data              – Very fast integer resolution
   – Good ionosphere model              at long ranges
   – Good Troposphere model
   – Integrity Check
   – Multiple reference stations
     at less than 200 mile
     baselines
      Code Differential Solution
  0




 50




100




150




            0    50   100   150
      Integer Resolution
  0




 50




100




150




         0   50   100   150
      Integer Resolution
  0




 50




100




150




         0   50   100   150
      Integer Resolution
  0




 50




100




150




         0   50   100   150
Models - Total Electron Count
Wx Model-Derived Wet Signal Delay Over
               CONUS




                            Courtesy, Dr. Sunil Bisnath
                            formally with USM, now at
                            Harvard Smithsonian
                            Astrophysical Observatory
                        Applications
• Transportation
   – Highway
      •   Automated Road Construction
                                        • Interior
      •   Intersection Collision Avoidance   – National Park Service
      •   Dynamic Mapping                        • Monitoring subsidence
                                                   of critical monuments
      •   Digital Highway Measurement
          Vehicle                                • Real-time boundary
                                                   marking
   – Railroad
                                             – Fish and Wildlife Service
      • Track Defect Monitoring
                                                 • Monitoring critical
   – Maritime                                      habitat
      • Under keel clearance                     • Biological Assessments
• USDA                                  • EPA
   – Agriculture                             – Hazardous Material Spill
      • Precision Farming                      containment
      • Autonomous Farm Vehicles
                                        • Etc.
   – USFS
      • Logging boundaries
      • Infestation monitoring
                 Summary
• HA-NDGPS signal successfully broadcast from
  multiple locations
  – State-of-the-Art modulation
  – Reliable diplexing technology
• Developed new atmospheric modeling
  approaches
• Accuracy better than 10 cm horizontally, 95%
• Availability above 99.9%
• Implementation cost <$100,000 per site
      Contact Information
                 Jim Arnold
       Federal Highway Administration
   Turner-Fairbank Highway research Center
              McLean, VA 22101
                (202)493-3265

                Phase I Test Report
     http://www.tfhrc.gov/its/ndgps/02110/index.htm
              Phase II Test Report
http://www.tfhrc.gov/its/pubs/05034/index.htm
Applications
The End
            HIGH ACCURACY - NDGPS
                              Whidbey Is
                            Wenatchee                                                                                                                                                                          Pattern
           Robinson Pt                    
                                                                                                                                       Upper                                                              Penobscot
                                                     Polson                                                                          Keweenaw                                                                   
                                      Spokane                                                                           Wisconsin
       Fort Stevens             Appleton                      Great Falls                             Edinburg                               Whitefish Pt
                                                                                                                                                                                               Middlebury  Brunswick
                                                                                                                              Point
                                                                                                                                                   Neebish Island
                                                                                                Medora                                                                                           
                                                                                                                                                   Cheboygan                                            Portsmouth
                                                                                                                       Pine
                                                                                                                                  Sturgeon Bay                                                       
                                             Weiser                            Billings                               River                            Saginaw                          Hudson
                                                                                                             Clark                                                                                          
                                                                                                                                          Medford                     Bay                  Falls              Acushnet
                                                                                                                            St. Paul                                         Youngstown
                                                                  Jackson                                                                                   Detroit               Elmira              Moriches
    Cape                                           INEL                                                        Ledyard                Milwaukee               
                                                                                                                                                                                                    Sandy Hook
    Mendocino 
                                      Jack                                                                                 Iowa City  Rock
                                                                                                                                                          Onondaga                         Hawk Run
                                     Creek                          Rawlins                                                                                                      Hagerstown  Reedy Point
                   Chico
                                        
                                                                                           Whitney
                                                                                                            Omaha          St Mary’s
                                                                                                                                        Island
                                                                                                                                                                     Cincinnati 
                                                                                                                                                                                              
                                                                                                                                                                                                       Cape Henlopen
                                     Austin    Myton            
                                                                                                                                                                                                Annapolis
                                                                                                                                                                      
                                                                                                                               Kansas
    Pigeon Point 
                                                                                                     
                                                                                                  Goodland
                                                                                                                Topeka
                                                                                                                          City                                   Monterey            Driver       Cape Henry
                                                Kanab                                                                                  St Louis
                                                                                                                                                          Louisville        
                                                                               Pueblo 
                          Bakersfield                                                                                                                                                  
                                                                                                                                                                                Greensboro   Fort Macon
     Point Arquello                                                                                           Canton                               Hartsville                             New Bern
                                                      
                                                                                                                                     Fayetteville                             Ashville
                               Essex                                                                            Sallisaw           Memphis 
                                                 Flagstaff                 Albuquerque                                                                                                     Kensington
                                                                                             
                                                                                                                                                 
                                                                                                                                                                                         Charleston
                  Point Loma                                                                                                                    Bobo
                                                                                            Summerfield                                                  Hackleburg           
                                                   Tucson                                                                                                                    Macon
                                                                                                                    Munday Vicksburg            Grady                               Savannah
                                                                                                                                      Millers Ferry
                                                                            El Paso         Odessa
                                                                                                                                                     
    Caretaker Sites                                                                                                                                Mobile
                                                                                                                                      English Turn Point                                  Cape Canaveral
                                                                                                  Langtry
   New Site                                                                                                        Galveston                                         Egmont Key
   Coast Guard Site                                                                                                                                                                            Miami
                                                                                                                        Aransas Pass
    Green - Operating
                                                                                                                                                                                  Key West 
    Red – Planned
    Dark Blue – HA-NDGPS Installed
    Light Blue – HA-NDGPS Planned
               The Broadcast
• Broadcast Code and Carrier Phase Data
     • Capability to broadcast all observables (L1,L2C,L5, and
       others) contained in less than 1000 bits
     • Data rates - 1KBPS
     • Initially L1 and L2-P(Y) observables are broadcast
• Utilize an Advanced Broadcast Link
     •   Data synchronized to GPS time
     •   Carrier calibrated with GPS to sub-hertz levels
     •   Spectrally efficient modulation (raised cosine MSK)
     •   “One second data” in compact mode
                 Add Ons
• National Geodetic Survey:
  – Replacing Brass Survey Markers
  – Continuosly Operating Reference Station
• GPS in Weather:
  – Troposphere and Ionisphere Delays
  – Troposphere delay correlated Atmospheric Water
    Vapor,
• Plate Boundary Observatory:
  – Used to measure plate movement.
• Etc.

				
DOCUMENT INFO
Shared By:
Categories:
Tags:
Stats:
views:2
posted:8/30/2012
language:English
pages:29