Navigation-aware guidance and control for autonomous spacecraft operations near non-cooperative targets

A Guidance and Control (G&C) architecture is proposed to enable far to close range proximity operations around non-cooperative space targets. The translational control task relies on a novel formulation of the zero-effort-miss/zero-effort-velocity algorithm in which the optimal control action determination relies on the Clohessy Wiltshire relative motion model. The translational control is navigation-aware thanks to the introduction of a dead band which is dynamically adjusted by propagating the current covariance estimate up to the arrival point. The G&C architecture is also integrated with a Kalman filter for the estimation of the relative translational motion, thus realizing a complete Guidance Navigation and Control architecture. The performance of the proposed architecture has been validated in a high-fidelity numerical simulator in both far and inspection scenarios in LEO. Results highlight the effectiveness of the architecture in reducing the number of required firing cycles, and, consequently, the propellant consumption, thereby enhancing the mission lifespan. Indeed, in both simulated scenarios, the control accuracy does not exceed 0.25 % of the range, even though the actuation system does not apply any control accelerations for almost half of the trajectory.