Development of GNC for Optimal Relative Spacecraft Trajectories

Abstract

Satellite rendezvous and proximity operations (RPO) require Guidance, Navigation, and Control (GNC) systems that can effectively and efficiently manipulate a spacecraft's position with respect to another space object. This study develops a modular spacecraft GNC architecture capable of utilizing various combinations of optimal guidance, feedback control, and navigation filtering subsystems. To demonstrate the architecture, the system is implemented in simulation and is shown to be capable of commanding RPO maneuvers in a highly constrained space environment. A complex rendezvous scenario is examined using a variety of controllers, navigation filters, and sensor combinations. The scenario considers two spacecraft: a maneuvering inspector spacecraft, and a non-maneuvering resident space object (RSO). The inspector must navigate through a debris field, avoiding pre-determined keep-out zones while on an optimal path to rendezvous with the RSO. To do this, the proposed GNC architecture operates by tracking an optimal reference trajectory, generated by the guidance subsystem a priori. Two different types of full-state feedback controllers are compared to track the desired trajectory. A full state estimate is provided by any of four different types of navigation filters using simulated measurement information from on-board sensors. Four different types of sensor suites are simulated, capable of producing combinations of position, velocity, angles, and range measurements. Results demonstrate the system's ability to track an optimal trajectory, as well as the ability to quickly and easily modify the architecture using different options for each GNC subsystem. The architecture is intended to serve as a basis for future GNC research for satellite RPO.