Filter coordinate frame based EKF method for celestial autonomous orbit determination

A novel autonomous real-time orbit determination method for deep space probe based on filter coordinate is proposed in this paper. This method is a variant of the traditional autonomous orbit determination based on extended Kalman filter. The stability of filter process is enhanced by adjusting the reference frame, termed as filter coordinate frame (FCF) in this paper, in each filtering cycle. The key of this method is to find a proper FCF, so that the expansion point of state equation and observation equation can be mapped to fit position, which improves the linearization and dicretization process of traditional EKF. In the simulation, this novel method is applied to cruise phase of lunar probe, the result shows its advantage in stability compared with the traditional method based on EKF.