Autonomous Collision Avoidance for Rendezvous and Docking in Space Using Photonic Mixer Devices

An autonomous collision avoidance system that is based on a Photonic Mixer Device camera is presented. It is specially designed for close range maneuvers in space, like rendezvous and docking and on-orbit servicing. The 3D imaging sensor provides relative position and orientation information of an observed target in close vicinity. Pose estimation, trajectory prediction and collision detection are performed on-line and serve as input to the collision avoidance system. In the event of an imminent collision, the required velocity corrections (AV) to perform a collision avoidance maneuver are calculated. Different trigger criteria like a cone-shaped approach corridor and a velocity profile are taken into account. AV computation is based on Hill-Clohessy-Wiltshire equations with the targeted hold point on V-bar as parameter. The system has been implemented in a complete framework including camera-based pose estimation and collision detection. Hardware-in-the-loop tests have been performed in a setup consisting of two industrial manipulators equipped with a Photonic Mixer Device camera and a satellite mockup model.