Two-stage estimation of spacecraft position and velocity via single station antenna tracking data

In this study, a two-stage approach for estimation of spacecraft's position and velocity by single station antenna tracking data is proposed. In the first stage, direct nonlinear antenna measurements are transformed to linear x-y-z coordinate measurements of spacecraft's position, and statistical characteristics of orbit determination errors are analyzed. Variances of orbit parameters' errors are chosen as the accuracy criteria. In the second stage, the outputs of the first stage are improved by the designed EKF for estimation of the spacecraft's position and velocity on indirect linear x-y-z measurements. Two recursive EKF algorithms are examined: the first designed filter estimates the position and velocity of the spacecraft on direct nonlinear range-azimuth-elevation measurements; the second one carries out the estimation on indirect linear x-y-z position measurements. The examined filters are compared through geostationary satellite orbital motion simulations, and the recommendations on their application for various spacecraft missions are given.