The Research Of Star Image Locating And Identifying Technology

The Celestial Positioning System based on star sensor is a very valuable positioning system because of its advantages of anti-electromagnetic interference, good hidden performance and high reliability. The key technology of the star sensor is star image processing and identification; the positioning precision is restricted by the accuracy of centroid extraction of star point in star image. The technology of the star image processing and the centroid extraction of star point are mainly studied in this paper.Based on lots of references, the feature of the star image and the noises are analyzed in this paper, and the spatial domain filter algorithm is used to denoise the star image; the way how to get the best background threshold is given according to the feature that the histogram of the star image has two peak values; the cross-projection star point separation algorithm is provided to solve the problem that the star points which are too close to each other are easily to be identified as one point, and this algorithm has been proved effective; this paper provides a star point subdivision method based on Gauss surface fitting, and the simulation results indicate that this method has high accuracy in single star subdivision. To the problem that motion blur exists in the star image taken on the ground, this paper advances that using Radon transformation and autocorrelation computing method to estimate the parameters of the degenerate function of motion blur, the simulation achieves good results. At last, this paper discusses a multi-triangle star identification algorithm based on main star-pair and provides a method to establish guide star database for this algorithm.