Autonomous Navigation of Spacecraft Constellation with Decentralized Unscented Information Filter

Potential application of inter-satellite links and X-ray pulsars on spacecraft constellation is illustrated based on distributed observation and the decentralized unscented information filter. X-ray pulsar time of arrival observation and inter-satellite pseudo-range are used as measurements, with consideration on clock timing error and inter-satellite link availability. Decentralized unscented information filters are derived and used to conduct the estimation computation, which allows each spacecraft only need to estimates local dynamics states, using local measurements and estimation information from other spacecraft nodes. This novel scheme greatly enhances computation efficiency and robustness. Feasibility and advantage of the proposed scheme are demonstrated by numerical simulation on a medium Earth orbit constellation mission. Simulation results also show that availability of inter-satellite links is essential to navigation performance improvement.