Initial Orbit Determination Using Simplex Fusion

Abstract

A new Initial Orbit Determination (IOD) method for angles-only observations is presented. This method is based on an adaptive Nelder-Mead simplex optimization technique for fusion of multiple observations from one or more acquisition satellites. The resulting solution characterizes the target orbit as a standard state vector. The algorithm is tested under a variety of scenarios, including acquisition orbits in Low Earth Orbit (LEO) and Geostationary Orbit (GEO), targets in GEO, both coplanar and non-coplanar cases, number of observations varying from 3 to 8, and time between observations varying from 60 to 1800 seconds. Observation error is varied in all cases to characterize the performance of the algorithm given varying angular resolution error. The simplex fusion algorithm is shown to perform well in a variety of cases when multiple acquisition satellites are used. Special emphasis is placed on GEO to GEO observations where the acquisition and target are in coplanar orbits. This new IOD method supports Space Situational Awareness (SSA) capabilities by enhancing performance in scenarios with multiple observation satellites for challenging GEO to GEO IOD scenarios.