Design and Testing of the Star Trackers for the SEAM Nanosatellite

Abstract: Star trackers are instruments for attitude determination and are a must for spacecrafts where
precise attitude knowledge is needed. Star trackers take accurate images of the stars and then
perform image processing and pattern recognition in order to accurately determine the attitude.
This requires high processing power, size and mass of the instrument, which are limited on
cubesats.
In this thesis work the sensor of a star tracker has been characterized, and calibration and
image correction procedures that require low processing capabilities have been developed. The
thesis work also includes the design of the star tracker in CAD software, with special attention
being payed to the baffle due to the limited size available and the importance of stray radiation
suppression. Stray radiation suppression is especially important due to limited ability for corrections
on image level. Furthermore, a method for processing the used star catalog has been
developed so the stellar brightness in the catalog corresponds to the brightness detected by the
star tracker.