Application of the Extended Kalman Filter to Several Formulations of Orbit Determination

摘要

Various sets of orbital elements are considered as state variables, and particular attention is given to two sets based on velocity space concepts. The properties of these sets are examined in detail and compared in the orbit determination context. Successful orbit determination is demonstrated using both of these sets, as well as the conventional set of position and velocity components. Although the velocity-space sets perform acceptably well, the conventional set is somewhat better in the cases studied. However, the conventional set is shown to be susceptible to an initial transient causing divergence. A simple technique is shown to alleviate the problem. Various sets of observables are applied to the determination of low Earth orbits, and, with typical amounts of measurement noise, the best set is shown to be azimuth, elevation, and range. Finally, the use of measurements from multiple sites is shown to significantly improve the orbit determination accuracy.