Improved Orbit Estimation Using Angles-Only Observations and Its Application to Low Earth Orbit Satellites

Angles-only observations of simulated LEO satellites for short-arcs are used for orbit estimation. Multiple stations and multiple passes cases are handled. During the first passes, initial orbit determination (IOD)is applied. For the following passes, beside classical prediction of the orbit at the observation time, a modified prediction of the orbit which finds the closest point to the observed angles along the trajectory is used in Unscented Kalman Filter (UKF). Finally, a logic is proposed which selects the most suitable result by means of estimation error between UKF using standard prediction, UKF using modified prediction and forgetting the previous estimation and applying IOD to the current pass. The numerical results of the IOD for single and multiple stations and the performance comparison of the UKF and the proposed logic using multiple passes are given at the end of the paper.