A charge coupled device star sensor system for a low earth orbit microsatellite

[摘要] ENGLISH ABSTRACT:Star sensor systems provide extra accuracy to the attitude determination and controlsystems of spacecraft These systems are generally complex and costly. This textdescribes the development of a low cost CCD star sensor system to meet the needs of alow 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 sophisticatedequipment possible.An investigation was done into the system as a whole with more detailed study of thecamera electronics, processing of the stellar image and pattern recognition techniques forfinding the attitude. In all sub-sections of the system an attempt has been made tooptimise the space of electronics and processing time of algorithms in keeping with therequirements of a micro satellite.Algorithms for image segmentation, centroid determination, pattern recognition andattitude calculation were implemented and developed. A prototype star camera wasdeveloped using the TC211 CCD and a Cosmicar lens in order to gain experience in CCDcamera 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 sensorsystem for a micro satellite is within reach of a small project group with limited resourcesand that this paper could serve as basis for such a venture .

[发布机构] Stellenbosch University