<h2>AAS  96-152</h2><h2>ADAPTIVE ORBIT DETERMINATION FOR INTERPLANETARY SPACECRAFT</h2><h4>P. D. Burkhart and R. H. Bishop, The University of Texas at Austin</h4><h2> Abstract </h2>The goal of this work is to increase the accuracy of interplanetary orbit determination while utilizing only radiometric data.  An adaptive orbit determination approach (based on the Magill filter bank) has been developed to meet this goal. The Mars Pathfinder mission is utilized to demonstrate the effectiveness of the adaptive filter bank in determining process and measurement noise variances based on the tracking data.  Results for the range case show that this approach is effective in selecting the noise variances that match those used to generate the data.  Results for the Doppler case are not as conclusive,  due primarily to linearization errors.<br><br>