Design and Performance Assessment of Guidance Algorithms for Vision Based Rendezvous

This paper deals with guidance and control design for a rendezvous mission in circular Mars orbit. Generally safety requirements and more specific constraints dictated by the on- board camera sensor have suggested the implementation of tailored guidance and control algorithms, especially for the trajectory control function. These algorithms, based on the travelling ellipse formulation of the relative motion, allow recovering trajectory dispersion while keeping the chaser into an inherently safe path. They have been tested with respect to the expected navigation accuracy and have shown a very robust behaviour. Trade off analysis versus a more classical approach and thorough validation has been performed in a realistic Mars Sample Return scenario. Satisfactory results in terms of fuel consumption, robustness and safety have been obtained. Secondly, attitude and trajectory controllers, synthesised for all the mission phases, are also presented. These controllers take into account sensor noise and the presence of flexible and sloshing modes, as well as the coupling between position and attitude for the final approach before docking..