A novel decentralized relative navigation algorithm for spacecraft formation flying

This paper presents a novel decentralized relative navigation algorithm. The relative motion equations are derived in the Earth-Centered-Inertial frame. The relative measurements contain not only the line of sight and range between the deputy and the chief, but also the ranges among different deputies. This helps to improve the redundancy and accuracy of the relative navigation for spacecraft formation flying. In decentralized estimation algorithm, it is necessary to transmit the global states in the formation to linearize the ranges among the deputies. A sigma-point method is used to account for the uncertainty in the estimated states of other spacecraft. The relative measurements are coupled with the relative motion equation in a novel decentralized filter to determine the relative position and velocity. Simulation shows that the proposed novel decentralized estimation algorithm provides better performance than the traditional iteration algorithm.