Stellar Location And Identification Algorithm In Celestial Location System

Celestial navigation with its passive independent measurement features, has wideapplied in field of spaceflight and navigation. With the development of technology,celestial location is used to determine the geographic longitude and latitude byastronomical information, and widely applied in field of geographical informationmeasurement (longitude and latitude, gravitational field, etc.). This paper mainlyfocuses the analysis of star image, which is taken by high-precision CCD digital zenithcamera. Relevant algorithms have been designed and implemented, the stellar locationand identification in observation star image have been achieved, which support thesolution of celestial location information.Based on the principle of celestial location method, the requirements of staridentification are analyzed, and an overall scheme including the preprocessing of starimage, the positioning of stellar target and star identification, is designed. Thepreprocessing of star image is achieved via the analysis of image noise and theimplement of gray correction and image enhancement. Though the analysis of imagehistogram, an algorithm of background segmentation based on the estimation of noisecharacteristics is designed, and combining with connected domain stellar targetextraction is realized. Different subdivided locating methods are simulated and adetailed comparison is carried out, because of the large amounts of image data a suitablealgorithm to the project is found. Based on the analysis of existing triangle matchingalgorithm and according to the actual, the improvement of star triangle identificationalgorithm is used to increase the system performance. Finally testing software iscompleted by integrating all parts. After testing with actual images, requirements areachieved.The star subdivided positioning and stellar automatic identification is realized inthis paper, which have made a foundation for the celestial location system. The result ispractical and referential meaning for astronomical image processing.