Angles-only relative navigation and closed-loop guidance for spacecraft proximity operations

•A closed-loop guidance scheme based on angles-only relative navigation is proposed.•Analytic expression of the observable condition for the relative state is derived.•Coupling relationship between angles-only navigation and guidance is developed.•Accurate navigation and precise guidance are confirmed by Monte Carlo simulations.•The sensitivities of the uncertainties and parameters are presented and discussed.

This research investigates angles-only relative navigation and closed-loop guidance algorithm for spacecraft mid-range orbital proximity operations when the orbital maneuver allows for range observability. Emphasis and contribution are on developing angles-only relative navigation and guidance coupling algorithm in the context of Clohessy–Wiltshire and Tschauner–Hempel dynamics. Observability analysis of the relative state is done and the general mathematical expression of the observable condition is obtained. Coupling relationship between the angles-only relative navigation and the multi-pulse sliding guidance is discussed and its analytic expression is derived. A novel closed-loop guidance scheme is designed based on the coupling relationship and unscented kalman filter. Two-body Monte Carlo simulations are conducted to evaluate the validity and test the performance of the closed-loop system. The sensitivities of the navigation and guidance accuracy to the line-of-sight angles accuracy, initial separation and initial state uncertainties, number of pulses, and dynamics are presented and discussed.