Journal of Guidance, Control and Dynamics vol:36 issue:2 pages:476-484
AIAA Guidance, Navigation and Control location:Portland, OR date:8-11 August 2011
A robust and fast algorithm to solve the lost in space problem for star trackers is presented in this paper. The algorithm is based on an image processing technique, the Shortest Distance Transform, which transforms the camera image into a 2D look-up table. The information from the database can then be efficiently passed into this table to compare the camera image with the database. This approach results in an algorithm which is robust to false stars, distortions on star positions and failure of registration of bright stars. As an example we state the correct determination of over 99% of camera images when 400 false stars, distortions of 300 (1σ) arc seconds are present and the brightest star is missing in the image. In case of incorrect determination, a very reliable criterion indicates that the determination step has to be repeated. The robustness of this algorithm can allow the use of star trackers in environments with high radiation. It is also a valuable contribution to the expanding field of small satellite projects where the low-cost camera components are more prone to error and registration of false stars. Small satellites using this algorithm can acquire great functionality at low componentcost.