Vision based autonomous guidance algorithm for terminal descent phase of soft lunar landing

In this paper an autonomous re-targeting algorithm is presented for the terminal descent phase of the lunar soft landing. A sensor based image processing unit provides a safe landing site over the Lunar territory. The guidance objective is to drive the spacecraft safely to the designated location while maintaining vertical orientation. The terminal descent phase is divided into three intermediate sub phases. During phase I, the vision sensor and image processing unit is activated. Two independent image processing techniques are used to generate a hazard mask of the landing territory. The mask generation involves morphological and local variance based techniques which are computationally efficient and suitable for real time applications. Phase II and III generate a fuel optimal on board guidance command that drives the vehicle towards the detected safe location with near zero velocity.