Design And Realization Of Star Recognition Algorithms Based On CCD Star Tracker

Nowadays numerous independent CCD star trackers were applied widely on the satellites. The star tracker was commonly considered as a kind of intellectualized attitude sensor for it comprises microprocessors. It can determine the orientation of satellites by star light vectors. Because of its high precision of orientation, without cumulative error and the capability of getting back from failure rapidly, the star tracker has been concerned more and more attention in the fields of aviation, spaceflight and military. The star identification technology based on CCD star tracker was investigated in this paper.Some key problems in the field of star identification such as the selection of guide stars, how to simulate the star map in PC and how to design method with high flexibility and precision were considered in the paper. The main work is as follows:The guide stars selection algorithm based on Support Vector Machine (SVM) was discussed in this paper. Some principles that must obey in the selection of guide stars were summarized after the distribution of stellar in the celestial sphere was analyzed in detail, and the disadvantage of magnitude filtering method was pointed out. Based on in-depth discussion of SVM, a new method was put forward for building the catalogue of guide stars. It was validated from experimentation that the method can not only satisfy the demand of star identification but reduce the memory capacitance of the catalogue.In order to implement star recognition experiments which based on star tracker expediently, this paper adopted instantaneous stellar coordinate for computer simulation of star-map. Also based on the translation of space coordinate systems and the collinear equation in photogrammetry, computer simulation of imaging process of CCD camera was discussed in this paper. And it was indicated that the method mentioned in the paper has a high accuracy.A new star identification method which based on the character of the triangular and a new method of searching the characters were testified in this paper. It can be concluded that the new method lessons the redundancy of recognition and it is a rude star identification method.Based on a new method of calculating the fitness of every individual in the colony, the genetic algorithm was developed in order to star identification. The author analyzed the feasibility and summarized the advantage and disadvantage of this method in this paper, and some improvement was presented for future research.