Autonomous navigation method of lunar lander using multi-scale optical flow

Aimed at the lunar lander's precise navigation task during the entry, descent and landing (EDL) phase, a vision navigation method using multi-scale optical flow is proposed. During the descent phase, there exists large relative motion in the image sequence captured by the CCD camera mounted on the lander. The original optical flow method can not satisfy the requirement in both accuracy and robustness. An image wavelet pyramid based multi-scale optical flow is introduced to make the features can be tracked between images with large motion. By using the robust least square method, the parameters of the relative rigid motion can be precisely estimated. The simulation results show that the vision navigation method is fast and effective for the autonomous navigation task during the EDL phase.