Bearings-Only Guidance in Cis-Lunar Rendezvous

The current plans of returning to the Moon involve rendezvous and docking/berthing operations with a passive permanent station, whose targeted orbit is a Near Rectilinear Halo Orbit. In this work a preliminary guidance algorithm for the close-range rendezvous phase is proposed, based on a sample mission application, assuming the active chaser can measure relative angles only to the target. The navigation performance is affected by the maneuvers performed because their execution is necessary to make the problem observable. The relative motion equations with third body perturbation are considered directly in the guidance algorithm, with the additional aim of improving observability during the approach trajectory. Numerical simulations are presented to validate the proposed methodology.