| Star sensor is one of the most precise sensors for measuring spacecraft attitude. Compared with other sensors, star sensor is autonomous and has no attitude error accumulation. Star pattern recognition is one of the key technologies in star sensor research and development. It is deeply investigated in this dissertation, main contents of this dissertation are as follows:General hardware structure of the star sensor is analyzed. The hardware of the star sensor is mainly divided into two parts. The second part's main functions are collecting and preprocessing star maps, and picking-up the star centroid. The second part's main functions are carrying out the star pattern recognition algorithm and calculating the spacecraft attitude.Typical star pattern recognition algorithms and methods of constructing star database are investigated. KMP (Knuth-Morris-Pratt) algorithm is used in star recognition. This method not only overcomes the disadvantage of low success of recognition, but also reduces the recognition time.However, the most information in guide star database is useless for star pattern recognition. And furthermore, star images, which are not identical to the sub-areas in the guide star database, can not be recognized with the method. For these reasons, new star pattern recognition is presented. Some bright stars are selected as main stars from entire celestial sphere, and some others as subaltern stars. The influence of star map's eddy and movement is avoided by this method. The original 0-1 star database is compressed, and the memory room reduces bitterly.The information of star's location is get after the star pattern recognition, then the attitude of the spacecraft needs to be calculated. In this dissertation, three typical modes to express attitude are analyzed, and then several kinds of typical algorithms of calculating the attitude are proposed and compared. They are q- algorithm, QUEST algorithm, TRIAD algorithm.
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