Autonomous navigation and control in halo orbit based on XNAV

To improve the independent capacity of the halo orbit spacecraft, we propose an autonomous navigation and control system based on the X-ray pulsar-based navigation (XNAV) principle. XNAV theory is applied in the construction of a measurement equation. The full ephemeris dynamical model is adopted in the establishment of the system state equation. We use the two-level differential correction method to obtain a nominal halo orbit in the inertial coordinate system. Based on the differential correction method, the halo orbit spacecraft is controlled using the navigation results from XNAV and the small thrust propeller. A numerical simulation is carried out in the Earth-Moon L2 halo orbit. The results demonstrate that the proposed method can accomplish autonomous navigation and control tasks effectively and the spacecraft can be maintained in the nominal orbit.