Selecting Optimal Inspection Trajectories for Target Observation

Abstract

A challenging aspect regarding proximity operations such as on-orbit servicing, refuelling and dismissal is the selection of optimal trajectories. The path should be conveniently followed by making use of sensors and actuators available on-board Optical hardware has been lately demonstrated to be both accurate and reliable for determining pose estimation in space proximity operations. Nevertheless, when passive cameras are used, accuracy is achieved through clear images which are obtained if the target is in favourable relative illumination conditions. The goal of this work is to design an optimal docking trajectory to an uncontrolled, non-cooperative, free-tumbling satellite. This trajectory should satisfy initial and final constraints, avoid collisions with the target and be optimal in terms of propellant consumption and relative sunlight viewing conditions. To this aim, an inverse optimization method based on polynomial parameterization of the trajectory is used inside a multi-objective genetic algorithm. The effect of the favourable illumination conditions on the camera measurements noise will be discussed. A comparison is carried out with a trajectory obtained from a single objective optimization. The significant inclusion of the constraint about illumination conditions, with relevant effect on the camera measurements noise, is discussed and evaluated.