<h2>AAS 95-371</h2><h2>The Determination of Precision Mean Element Sets from GPS Receiver On-board Navigation Solutions</h2><h4>S. Carter, P. J. Cefola and R. Proulx, The Charles Stark Draper Laboratory, Inc., Cambridge, MA</h4><h2> Abstract </h2>This paper examines the use of onboard GPS navigation solutions as observation data for high precision ground-based orbit determination.  Semianalytic and special perturbation satellite theories are employed to develop precision element sets for the Ocean Topography Experiment (TOPEX) and Extreme Ultraviolet Explorer (EUVE) satellites from using GPS on-board navigation solutions.  Evaluation of the derived solutions is accomplished by abutment checks on EUVE data (100 meter position errors) and comparison of TOPEX solutions to a Precision Orbit Ephemeris generated by Goddard Space Flight Center (10 meter position errors).  These result suggest the feasibility of eliminating the cost and complexity associated with differential GPS concepts and enhanced onboard GPS receiver software for certain moderate accuracy satellite navigation applications.<br><br>