Abstract: By using four non-coplanar reference points and an optical image sensor, this paper investigates the optical measurement method. Based on the assumption of scaled orthographic projection, the mathematical model of optical imaging is simplified by representing the relative attitude using quaternion. Then a closed-form solution is derived, and correct terms are added to obtain more accurate estimates for the pose parameters. In the last, the solution has been validated by using mathematical simulation, and simulation results show that this solution is simple and effective and the proposed solution is more suitable in on-board real-time computation.

Key words: spacecraft, rendezvous and docking, optical measurement, quaternion, pose determination