SEARCH-LESS ALGORITHM FOR STAR PATTERN-RECOGNITION

A fast and robust star identification technique (which does not use a searching phase) is presented for a spacecraft equipped with a wide fi eld-of-view star tracker. The algorithm, which identifies stars within a large star catalog using stars' angular separation only, consists o f two identification processes: the K-vector Star-Pair Identification Technique (SPIT), which, for any observed angular separation, selects an admissible star-pair set from the star catalog; and the subsequent Reference-Star Star-Matching Identification Technique (SMIT), which pe rforms the identification process based on a subset of all of the admi ssible star-pairs. The K-vector SPIT, which uses an appropriate devise d vector of integers, does not require a searching phase. The best-fit ting SPIT, which uses a best-fitting criterion to reduce the searching phase, is also presented. The resulting robustness of the algorithm i s such that, after spikes are deleted, at least three true stars are s till available. An overall software block diagram of the proposed syst em is depicted as well as the results obtained by extensive tests.