Observability analysis of autonomous navigation system of interplanetary spacecraft

In this paper, an autonomous navigation scheme for interplanetary spacecraft based on the Sun line-of-sight vector measurement is proposed. In order to prove that the directional data alone can completely determine the spacecraft orbit, an analytical observability analysis is implemented through the partial derivative of the measurement equation. Then, a numerical local observability analysis is derived from the Lie derivative. Also presented is a global observability analysis by introducing the condition number of the measurement matrix. Finally, simulation results demonstrate the validity of the proposed navigation algorithm.