DRO Initial Orbit Determination Using Two-Level Admissible Regions Constructed by Orbit Characteristic Parameters

The Distant Retrograde Orbits(DROs) have become strategic targets for various countries due to their unique orbital configuration and specific properties. Therefore, providing a rapid and accurate initial orbit determination(IOD) scheme for DROs is a critical step in Earth-Moon space situational awareness. Given the instability of traditional IOD methods when simultaneously addressing the challenges of DROs and very short arcs(VSA), this paper proposes an IOD method based on constructing an Admissible Region(AR) from DRO characteristic parameters. This method sequentially constructs ARs based on characteristic parameters in both the inertial coordinate system and the synodic coordinate system to constrain the solution space. Within the final AR, an optimization algorithm based on observation-minus-computation(OC) residuals is utilized, integrating and predicting solutions while minimizing residuals, ultimately producing accurate DRO orbital data. By reducing the reliance on orbital integration typical of traditional methods, this approach lowers computational costs and enhances the simplicity and efficiency of solving the IOD problem for DRO.