X-ray pulsar-based navigation system/Sun measurement integrated navigation method for deep space explorer

Abstract

In order to enhance the autonomy and survivability of deep space explorers, an X-ray pulsar-based navigation system (XNAV)/Sun measurement integrated navigation system is proposed. In this method, the directional measurement of the line-of-sight of Sun, the Doppler radical velocity measurement, and the measurement from an X-ray pulsar are fused for navigation. A square-root unscented kinematic and static filter (SUKSF) is derived to optimally fuse the three types of measurements. SUKSF utilizes the unscented formation to reduce the impact of linearization error, and uses the square-root technique to enhance the computational stability. Compared with the federated filter, SUKSF can provide a globally optimal estimation result with less computation cost. Some simulations are performed to verify the proposed integrated navigation system, and the results have illustrated that the proposed method outperforms the navigation method employing only Sun measurement as well as XNAV.