In spacecraft rendezvous, bearings-only navigation generally suffers from a lack of observability in range direction. Therefore, dedicated orbital maneuvers are essential to improve the observability and meet the navigation requirement. This paper proposes a simple one-step guidance method for improving observability. A new cost that quantifies the observability is defined by exploiting a Fisher information matrix (FIM). The resulting delta-v solution, recursively obtained at every maneuvering instant, enables the mission to fulfill the navigation requirement as well as the safety requirement and the final boundary condition. Thanks to its low computational burden, the proposed guidance method can be easily extended to the closed-loop guidance/navigation system. The closed-loop formulation makes the tracking performance robust against the disturbances and the thruster model errors. Numerical simulations demonstrate the effectiveness of the one-step guidance and the extended closed-loop guidance in a v-bar rendezvous scenario. (C) 2020 COSPAR. Published by Elsevier Ltd. All rights reserved.