The Software Design Of Star Sensor Pose-ascertaining System

As a kind of vector attitude sensor, the star sensor gains popularity for its high accuracy, without attitude accumulative errors. With the development of satellite-lighting and autonomous navigation technology, the research of attitude detection system has been becoming the hotspot of inertia space technology.Using the star images shoot by star sensor, system can calculates the instantaneous direction of the star sensor axes through such steps as star detection, identification of star clouds and ascertainment of position, so it can decide the three abstract axes position of satellite. Designing a software system based on CMOS star sensor and ARM processor. Researching an improved star pattern recognition algorithm and the construct of guide star database.(1) Researching the star pattern recognition algorithm from two aspects: fully autonomous star identification and locally identification. The fully autonomous star identification algorithm is a development of triangle identification algorithm. Dispelling triangle similarity by introducing the clock geometry information of the triangular mode. The locally identification using the axes position detected by last star image to find the local sky covered by current star image, then matching the imaging stars with guide stars directly. System can switch in the two identification algorithms to improve the identification efficiency.(2) Researching the construct of guide star database based on star pattern recognition algorithm and the detection precision of star sensor. Constructing an index table based guide star database for layered matching. The database includes triangle pattern table, star position table and star-vector table.Covering the whole sky by the PC simulation software, and the simulation shows that the identification efficiency is 97%, and attitude detection precision is 0.01 degree. The system has imaged on the really sky, and the identification efficiency of serial Orion images is 95%. The experiment shows the algorithm can satisfy the command of satellite attitude detection system.