Sequential processing of inter-satellite doppler tracking for a dual-spacecraft configuration

The navigation of future interplanetary spacecraft will require an increasing degree of autonomy to enhance space system performance. A real-time trajectory determination is of paramount importance to reduce the risks of operations devoted to the exploration of celestial bodies in the solar system and to reduce the dependence and the loading on the ground systems. We present a technique for a sequential estimation of spacecraft orbits through the processing of line-of-sight relative velocity measurements that are acquired by the novel inter-satellite tracking system. This estimation scheme is based on the extended Kalman filter and is tested and validated in a realistic Mars mission scenario. Our numerical simulations suggest that the proposed navigation system can provide accuracies of a few meters in position and a few millimeters per second in velocity.