An autonomous optical navigation filter for a CubeSat mission to a binary asteroid system

The DustCube mission concept, which was the subject of previous studies done by the authors under ESA contract, is used here as a test case for demonstrating the autonomous navigation capabilities of a CubeSat platform within the binary asteroid system Didymos. In this work, a navigation filter is developed, which computes the s/c position starting from images of the two primaries, using both information on the line-of-sight to the target centroids and on the targets' range. The likelihood of the observations is then fused to the a-priori information coming from a reduced dynamic model, in a Kalman-like recursive filter. Expected performances of this filter, at the proposed parking orbit at 4 , are assessed through numerical simulations inside a high fidelity model of the Didymos system and assuming realistic values for the measurement errors. Results show the effectiveness of the proposed approach to meet the target accuracies of 10 in position and 5 / in velocity, which represent the requirements provided by the original mission analysis study.