Angle-Only Orbit Determination Method for Cislunar Orbits Under Observational Constraints

Cislunar space, due to its special dynamical properties, is an ideal location for space missions. High-accuracy orbit determination (OD) is a prerequisite to guarantee the successful implementation of cislunar space missions. The resources for observations of cislunar space are limited, impacting the OD performances. In this paper, an angle-only OD method is proposed for cislunar space under restricted observation conditions. Firstly, an angle-only OD model for cislunar space is established, and a local observability assessment method based on the Fisher matrix is proposed. Secondly, the observability of the ang-only OD in the cislunar space is analyzed based on the proposed local observability assessment method. A strategy for OD under restricted observation conditions is proposed to improve OD accuracy. Finally, the proposed method is successfully applied to solve the OD problem of a Near Rectilinear Halo Orbit (NRHO). The accuracy of OD under the same observation conditions is analyzed. Simulation results indicate that this method can effectively improve the accuracy of OD under restricted observation conditions. The proposed method can be potentially useful in future cislunar missions.