Feature-based Optical Navigation for Lunar Landings

Future soft landing missions to celestial bodies will demand a high accuracy in absolute navigation. In such missions, the long signal delays, loss of accuracy with distance and the possibility of Line Of Sight (LOS) blocking don’t allow for timely control decisions from the ground. Thus, to achieve high landing accuracy, the on-board Guidance Navigation and Control (GNC) system must be autonomous. Absolute optical navigation uses optical information (such as camera images) of the celestial surface, combined with target specific information (such as a reference map), to determine the state of the Spacecraft (S/C) in a body fixed global frame (e.g., Moon Centred Moon Fixed). This paper describes an approach to absolute optical navigation based on image features. Although the method can be used in other celestial bodies, the remainder of the paper uses the lunar case as exampl