Browsing by Author "Greyling, Barend Christiaan"
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- ItemA charge coupled device star sensor system for a low earth orbit microsatellite(Stellenbosch : Stellenbosch University, 1995) Greyling, Barend Christiaan; Steyn, W. H.; Stellenbosch University. Faculty of Engineering. Department of Mechanical and Mechatronic Engineering.ENGLISH ABSTRACT: Star sensor systems provide extra accuracy to the attitude determination and control systems of spacecraft These systems are generally complex and costly. This text describes the development of a low cost CCD star sensor system to meet the needs of a low earth orbit micro satellite. The attitude accuracy of this satellite is low (3 arc minutes) compared to other systems. This makes the use of cheaper and less sophisticated equipment possible. An investigation was done into the system as a whole with more detailed study of the camera electronics, processing of the stellar image and pattern recognition techniques for finding the attitude. In all sub-sections of the system an attempt has been made to optimise the space of electronics and processing time of algorithms in keeping with the requirements of a micro satellite. Algorithms for image segmentation, centroid determination, pattern recognition and attitude calculation were implemented and developed. A prototype star camera was developed using the TC211 CCD and a Cosmicar lens in order to gain experience in CCD camera design and show that such a low cost system is feasible. It was found that such a project for the development and implementation of a star sensor system for a micro satellite is within reach of a small project group with limited resources and that this paper could serve as basis for such a venture .