Abstract: In accordance with the highly nonlinear of orbit dynamics and the precision requirement of the autonomous orbit determination for navigation constellation, a parallel autonomous orbit determination method based on the dual direction range measurement was proposed. In this method, the unscented Kalman filter is used as the onboard estimation algorithm for each satellite to get its own state and the extra covariance used in this filter which is introduced by the priori orbit is given to ensure the filter stability. The simulation results show that the new method can maintain the long term autonomous orbit determination and the precision of the satellite orbits.

Key words:  satellite navigation system, autonomous orbit determination, unscented Kalman filter（UKF）, extra covariance