One-step rendezvous guidance for improving observability in bearings-only navigation

•The guidance problem for spacecraft rendezvous in bearings-only navigation is studied.•A simple and practical solution that improves observability is proposed.•A Fisher information matrix (FIM) is exploited to quantify the observability.•The resulting trajectory satisfies the navigation requirement as well as the safety requirement and final boundary condition.•A closed-loop guidance method is also proposed by integrating a filter for relative navigation.