Autonomous small body flyby navigation based on vector measurement and UKBF

For long communication delay induced by large distance from the Earth, autonomous navigation becomes a regarded technique for a spacecraft approaching a small body. In this work, an optical autonomous asteroid flyby navigation method is proposed based on line-of-sight (LOS) vector measurement. The LOS vector from spacecraft to target body is constructed by using optical navigation camera and altimeter. To avoid the model error of linearization and discretization, an UKBF (Unscented Kalman-Bucy Filter) algorithm is adopted to estimate the inertial position and velocity of spacecraft and target body. Observability of the navigation system is analyzed, and the proposed method is used for the simulation of Temple 1 flyby mission, theoretical analysis and simulation results demonstrate feasibility and effectiveness of the proposed method.