Simultaneous Estimation of Lunar Ephemeris and Satellite Orbits Using a DRO-Based LiAISON Method in Cislunar Space

The Linked Autonomous Interplanetary Satellite Orbit Navigation (LiAISON) technique enables autonomous absolute orbit determination through satellite-to-satellite tracking (SST) range measurements between two satellites when one is located in an asymmetric gravitational field.While traditional LiAISON studies assume a precise lunar ephemeris, this paper investigates the feasibility of autonomously estimating the lunar ephemeris (lunar orbit relative to the Earth) and satellite orbits simultaneously.The proposed approach utilizes an extended Kalman filter to process SST measurements in cislunar space, specifically involving distant-retrograde-orbit (DRO) satellites, and this paper evaluates lunar ephemeris estimation performance across SST scenarios and compares observability.Numerical simulations demonstrate that in an SST scenario involving two DRO satellites and a low-Earth-orbit (LEO) satellite using 90 d of SST simulated data with 0.5-m range noise, the lunar ephemeris achieves meter-level position accuracy.Additionally, the satellite orbit accuracy reaches 0.1 m for LEO and approximately 5 m for DRO satellites.Although the simulation results were obtained with several simplifications, these findings nevertheless demonstrate the efficacy of the proposed method for lunar ephemeris estimation and its potential to enhance the autonomy of satellite navigation in cislunar space.