Variable-fidelity sensors and observer uncertainty using touring multi-body periodic orbits to conduct cislunar SSA: preliminary study

Abstract

An accelerating interest in cislunar space and lunar orbit for civilian, commercial, and scientific missions requires a space situational awareness (SSA) architecture extending beyond geosynchronous orbit to promote space traffic management and safety. Space-based SSA in cislunar space is challenging due to difficulties associated with accurately estimating the position of the surveillance satellite, which is a foundational requirement for effectively performing the general SSA mission. Using multiple surveillance satellites with lower-fidelity sensors helps alleviate these concerns by aggregating multiple data sets with higher variance to achieve the same level or potentially improved accuracy as compared to fewer higher-quality sensors. A subset of Earth–Moon periodic orbits, herein identified as “touring” orbits, are used for an optical surveillance constellation with a target resident space object (RSO) in a L₁ Halo orbit. Angles-only measurement data are processed utilizing an extended Kalman filter to estimate the position of the RSO. The analysis focuses on assessing the effectiveness of different numbers of surveillance satellites using touring cislunar periodic orbits for conducting the SSA mission relative to L₁. Overall, this study finds that the use of an SSA constellation with low-fidelity sensors can match the performance achieved by a constellation featuring higher-fidelity sensors and reduced observer uncertainty for the observer orbits examined.