A dynamic accuracy measurement method for star trackers using a time synchronized high accuracy turntable

• Rui Lu, Jianfu Zhang, Xing Han, Yanpeng Wu, and Lin Li
• received 01/11/2024; accepted 04/11/2024; posted 04/12/2024; Doc. ID 507209
• Abstract: Star trackers are typically used in a spacecraft to provide absolute attitude information to the on-board attitude controlsystem for its high accuracy. The performance of the star tracker is rather important. Attitude incorrectness provided bystar trackers may lead to bad navigation with big deviations, even failure of satellites. Therefore, how to realize andverify the accuracy is crucial. As a matter of fact, it is difficult to validate accuracy of star trackers on ground, especiallyfor star trackers under high dynamic conditions. In this paper, an accuracy measurement method for star trackers under dynamic conditions is proposed, utilizinghigh accuracy swing table to provide reference to compare. To this end, swing table, star tracker, and the test equipmentare synchronized, in order to reduce systematic errors. As the motion trajectory of the swing table can be setbeforehand, initial attitude of the star tracker can be predicted through a set of coordinate transformations. As a result,the star tracker is able to keep tracking, regardless of the angular velocity of the swing table. This makes the statisticalsample points more sufficient and the results more reliable. Moreover it can evaluate the angular velocity of startrackers up to 20°/s. In comparison with the conventional method with simulated stars, this method utilizes realnavigation stars as observation targets making the measurement results much closer to the on-orbit performance. Lastbut much more important, it can also verify the performances of a star tracker in one experiment, such as sensitivity,static performance, capture probability and so on. Experimental results demonstrate that the proposed method iseffective, especially for high dynamic star trackers. Such a measurement environment is close to the in-orbit conditionsand it can satisfy the stringent requirement for star trackers under high dynamics