<h2>AAS 95-343</h2><h2>A Prototype Onboard Processor for LEO Control Using a GPS Receiver</h2><h4>R. G. Gist, S. E. Williams, M. D. Menn and C. C. Chao, The Aerospace Corporation, El Segundo, CA</h4><h2> Abstract </h2>This paper presents a prototype on-board processing system to station-keep a vehicle in a 1700 kilometer altitude orbit based on navigation information from an on-board GPS receiver system.  The target orbit is a member of the well-known class of "frozen" orbits.  Once significant deviation from the target orbit is detected, a bi-elliptic orbit correction is executed which maintains the frozen conditions.  A Kalman filter estimator for stabilized Keplerian parameters is used to simulate navigation of a satellite using GPS measurements.  Significant cost savings could be realized by a reduction of ground support required for such an autonomously navigated vehicle.<br><br>