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Global Positioning System Demonstration Receiver (GPSDR)

NSSDCA ID: 1992-052A-04

Mission Name: Topex/Poseidon
Principal Investigator:Mr. Lee-Lueng Fu


The Global Positioning System (GPS) Demonstration Receiver (GPSDR) on the TOPEX/Poseidon spacecraft was an experimental system provided by NASA which extracted pseudo-range (range plus a clock bias) from the transmission of the GPS Navstar satellites for precise orbit determination. The primary objectives of the GPSDR experiment were to demonstrate an alternate means of achieving precision orbit tracking accuracy and to provide significant enhancement to the ocean topography data. By using double-differenced range measurements from the anticipated 18-satellite operational GPS Navstar constellation and 7 or 8 ground stations, the global orbits for TOPEX can be determined to an accuracy of 10 cm. The GPS operates at 1227.6 MHz and 1575.4 MHz. The receiver was developed by Motorola for NASA JPL.

Alternate Names

  • TopexPoseidon/GPSDR

Facts in Brief

Mass: 28 kg
Power (avg): 29 W
Bit rate (avg): 0.7 kbps

Funding Agency

  • National Aeronautics and Space Administration (United States)


  • Earth Science: Geophysics/Geodesy
  • Engineering: None assigned

Additional Information

Questions and comments about this experiment can be directed to: Dr. Dieter K. Bilitza



NameRoleOriginal AffiliationE-mail
Mr. Lee-Lueng FuTeam LeaderNASA Jet Propulsion

Selected References

  • Wu, J.-T., and T. P. Yunck, Topex orbit determination and gravity recovery using global positioning system data from repeat orbits, J. Geophys. Res., 97, No. B2, 1973-1979, doi:10.1029/91JB02562, Feb. 1992.
  • Bertiger, W. I., et al., Gravity field improvement using global positioning system data from Topex/Poseidon: A covariance analysis, J. Geophys. Res., 97, No. B2, 1965-1971, doi:10.1029/91JB02563, Feb. 1992.
  • Born, G. H., et al., Topex: Observing the oceans from space, EOS, 65, No. 28, 433-434, doi:10.1029/EO065i028p00433, July 1984.
  • Topex/Poseidon mission description, in 1633-5, Rev. B, JPL D-601, Rev. B, JPL/NASA, Dec. 1985.
  • TOPEX/Poseidon Sci Work Team, Topex/Poseidon science investigations plan, in JPL/NASA, Sep. 1991.
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