Vision-Based Attitude Determination Using A SLAM Algorithm During Relative Circumnavigation Of Non-cooperative Objects

We approach the problem of a chaser satellite circumnavigating a target object in a relative orbit. The objective is to obtain a map of the scenario and to measure the reciprocal position of the chaser-target pair, in order to subsequently perform proximity operations (active debris removal, rendezvous, servicing, etc.) more reliably. This work analyzes the case of a target-chaser scenario in a closed Clohessy-Wiltshire relative orbit. The chaser satellite has a vision sensor and observes a set of landmarks on the target satellite: the control acts on the yaw-rotation of the detector. By defining a probability distribution over a set of feasible control trajectories, we perform a search for a near-optimal solution. At the core of this approach lies the cross entropy minimization technique for estimating rare-event probabilities, which iteratively approximates the sampling distribution towards regions of progressively lower cost until converging to the optimum. We present simulations of a tracking scenario, demonstrating the validity of the proposed control technique. Performance of the proposed policy is compared with the case of a non controlled sensor by evaluating the time spent under observation and the residual uncertainty bounds on the landmarks. Results confirm the validity of the proposed approach.