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Benefits Derived From Laser Ranging Measurements for Orbit Determination of the GPS Satellite OrbitWhile navigation systems for the determination of the orbit of the Global Position System (GPS) have proven to be very effective, the current research is examining methods to lower the error in the GPS satellite ephemerides below their current level. Two GPS satellites that are currently in orbit carry retro-reflectors onboard. One notion to reduce the error in the satellite ephemerides is to utilize the retro-reflectors via laser ranging measurements taken from multiple Earth ground stations. Analysis has been performed to determine the level of reduction in the semi-major axis covariance of the GPS satellites, when laser ranging measurements are supplemented to the radiometric station keeping, which the satellites undergo. Six ground tracking systems are studied to estimate the performance of the satellite. The first system is the baseline current system approach which provides pseudo-range and integrated Doppler measurements from six ground stations. The remaining five ground tracking systems utilize all measurements from the current system and laser ranging measurements from the additional ground stations utilized within those systems. Station locations for the additional ground sites were taken from a listing of laser ranging ground stations from the International Laser Ranging Service. Results show reductions in state covariance estimates when utilizing laser ranging measurements to solve for the satellite s position component of the state vector. Results also show dependency on the number of ground stations providing laser ranging measurements, orientation of the satellite to the ground stations, and the initial covariance of the satellite's state vector.
Document ID
20070031550
Acquisition Source
Glenn Research Center
Document Type
Technical Memorandum (TM)
Authors
Welch, Bryan W.
(NASA Glenn Research Center Cleveland, OH, United States)
Date Acquired
August 23, 2013
Publication Date
August 1, 2007
Subject Category
Lasers And Masers
Report/Patent Number
NASA/TM-2007-214971
E-16125
Meeting Information
Meeting: ION 63rd Annual Meeting
Location: Cambridge, MA
Country: United States
Start Date: April 23, 2007
End Date: April 25, 2007
Sponsors: Institute of Navigation
Funding Number(s)
WBS: WBS 439432.07.04.03.01
Distribution Limits
Public
Copyright
Work of the US Gov. Public Use Permitted.
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