Suboptimal Guidance for Orbital Proximity Maneuver with Path Constraints Capability

A suboptimal guidance strategy is applied to a 3D translation-only proximity maneuver for a spacecraft in a circular orbit. The approach combines the Inverse Dynamic in the Virtual Domain with the Sequential Gradient-Restoration Algorithm to generate, in realtime, quasi minimum energy trajectories. The maneuver scenarios are based on ClohessyWiltshire dynamic and considers a chaser spacecraft, with limited thrust, moving from an initial state to a final state within an assigned maximum maneuver time. The scenario is completed assuming a spherical keep-out-zone located in between the initial and final position. Resulting trajectories are compared to the optimal solutions obtained by pseudospectral methods. To test the disturbance rejection capability of this guidance strategy, simulations have been also executed assuming the presence of sensor noise and a disturbance force acting on the chaser. Simulation results are included, which show that the proposed approach is suitable for on-board real-time trajectory generation and guidance purposes.