Persistent, Robust Navigation & Control in Autonomous Rendezvous, Formation Flight, and Docking

Autonomous rendezvous and docking is a key technology for many important space missions such as space debris management, supply to the International Space Station, on-orbit satellite maintenance, and large-scale structure assembly and satellite networking. This proposal accounts for an active spacecraft, namely deputy, approaching a chief spacecraft in close-range rendezvous and in proximity autonomously, and simultaneously. A key enabling technology in these missions is autonomous rendezvous and capturing that requires precise position and attitude control. Two main innovations relative to the current state of the art are proposed: robust adaptive unscented Kalman filters using multiple sensors, and fault-tolerant finite-time pose control algorithms deployed via on-orbit flight software.nbsp;SCOUT is building fault-tolerant and robust 6-degree-of-freedom finite-time controllers to conduct proximity operations with faster, more accurate tracking performance and more efficient control energy consumption than the conventional controllers in the presence of actuator faults, parametric uncertainties of the system, and unknown external disturbances. Developing autonomous relative navigation systems for rendezvous, proximity operations, and docking will yield persistent, robust and precise pose (position and attitude) state estimations remotely. For close-range rendezvous, absolute and relative GPS navigations using GPS C/A code measurements will be developed while star-trackers and Inertia-Measurement Units (IMUs) are used for relative attitude estimations between the chief and the deputy spacecraft. SCOUT shall build real-time orbit determination systems for absolute GPS navigation using onboard GPS C/A code measurements, which can be used for supporting nbsp;autonomous navigation.