In-Orbit Motion Coordination Using Relative Optical Sensing and Bio-Inspired Feedback
Md Arif Billah, Imraan Faruque · 2025
Recent developments in satellite formation flying and rendezvous/proximity operations have led to a new era of space missions in low earth orbit characterized by proliferation of distributed systems. Satellite formation flying has traditionally enabled flexibility, efficiency, scalability and redundancy compared to a single satellite. Ensuring sustainability of the increasing proliferation will benefit from more diverse approaches to in-orbit motion coordination that reduce reliance on communication links and absolute position references. This study derives the non-linear relative equations of motion applied to a chief satellite and a deputy target in the LEO orbit and designs a feedback control system to facilitate multi-satellite relative motion coordination that provides a proof of boundedness rather than convergence to a rigid formation. To enable target rendezvous by the chief satellite, navigation capability is analyzed by designing an on-board optical sensing based feedback controller. This feedback is based on an optic flow signal used in bio-inspired feedback controlled systems to perform various aerial operations including autonomous flights, obstacle detection and avoidance, flight navigation, altitude estimation and has recently been extended to group motion. Optic flow is applied to on-board optical sensing in space as it is more compatible with less computationally-equipped platforms under appropriate sensor design limits. On-board optical sensors detect and measure the optic flow generated by the deputy target motion, which is then used to generate the required changes in the chief orbit to enable rendezvous with the target. The feedback control framework performance is analyzed by means of multiple numerical simulations on a realistic rendezvous scenario with a target in LEO orbit. The idealized optic flow equation is used in a spatially discrete environment with the target as the only point-mass object generating optic flow. Results indicate optic flow generated by the target can be used for continuous trajectory correction, and eventually rendezvous. Implementation of the system is performed in both ECI reference frame and the chief satellite's body-fixed rotating Hill-Clohessy-Wiltshire (HCW) frame. Initial results suggest stability of the relative dynamical system.