<h2>AAS 99-184</h2>
<h2>Bias Estimation Technique for Geosynchronous Orbit Determination                                                                                 </h2>
<h4>S. Kawase                                                                                                                                                                           </h4>
Communications Research Laboratory, Japan                                                                                                                                 
<h2> Abstract </h2>
Zero-calibration of range and angle tracking biases, which is essential for accurate orbit determinations, becomes feasible if we temporarily change the satellites longitude to the tracking station's longitude, or track two satellites in parallel and determine their orbits together. The former enables the station's bias parameter (or parameters) to be solved. Then, those of any other stations can likewise be solved and the satellite can be put back to its operational longitude. The latter enables all relevant bias parameters to be solved in one single batch of orbit determination. Bias-eliminated orbit determination will support navigation services using geosynchronous satellites and will improve the control of "overcrowded" orbits.