Evaluation and Performance Optimization of PMD Camera for RvD Application*

Over several decades spacecraft that have reached end of life have been adding space debris. There are spacecraft with precious functional payloads on-board but have lost the ability to actively control their attitude and orbit. Proposals have been made to either mitigate them or when possible extend their life by docking them with a service spacecraft. On-orbit servicing involves the challenge of bringing an active satellite in contact with a non-cooperative one. This requires the servicer to make observations of the target to be able to characterize target's motion and to prepare itself for docking or grasping maneuvers. The criticality of proximity operations require high availability of relative navigation information in real-time. This paper focuses on applying Photonic Mixer Device, a Time of Flight based 3D imaging sensor, for relative motion estimation of the target. While much research has been done on evaluation and characterization of PMD and other ToF based cameras, they are mostly restricted to terrestrial applications. The objective of the research activities done here are to understand the dynamics of the sensor and to adapt the camera to optimize its performance for scenarios typically encountered in RvD.