Using Star Identification Algorithms on ESTCube-2 Star Tracker

Abstract

This thesis estimates the feasibility and determines the expected performance characteristics of a star tracker for ESTCube-2 student satellite. It measures limiting magnitude for the ESTCube- 2 star tracker hardware and estimates the decrease in signal-to-noise ratio due to the spacecraft’s rotational motion using geometric modelling. The acquired limiting magnitude is used to determine the optimal parameters to use with the pattern recognition algorithms for star identification purposes. The work also develops a way of creating and structuring a reference database in an effective way. Test results indicate that using the acquired parameters, the star tracker will be able to determine spacecraft’s attitude for cases of slow rotation up to 5 degrees per second. Results also indicate capability of attitude determination up to 10 times per second. The spacecraft’s mission also contains a phase of fast rotation, during which the star tracker will no longer be able to produce accurate attitude estimates at all times. With the algorithm configurations recommended in the thesis the ESTCube-2 star tracker could still provide a valuable contribution to the attitude and orbital control subsystem while experiencing angular velocities greater than 5 degrees per second. Thus it may outperform state-of-the-art commercial nanosatellite star trackers in that particular situation.