Star tracker is a high-accuracy attitude determination device widely used in spacecraft. A traditional star tracker obtain the attitude angle by calculating the centroids of star spots on photo detector. However, the directional accuracy is limited to arc-second level. In this paper, we introduce an interferometric star tracker. The interferometric star tracker improve the attitude accuracy by using interferometric components, the interference components consist of two identical gratings and several wedge plates. Tiny change of incident angle can be sensed by detecting the relative intensity of spots divided by the wedge plates. Optical design and accuracy analysis of interferometric star tracker were illustrated in this paper. The theoretical analysis indicates that accuracy of interferometric star tracker depend on the grating distance, grating period and gray level. In the laboratory experiment, the results show that that the relationship between the light intensity of each spot and incident angle can be expressed as a sinusoidal function, and the gray level difference of each spot can reach 1500, which means the accuracy can reach '' 0.2 or even higher.

Date Published: 5 November 2018
PDF: 9 pages
Proc. SPIE 10815, Optical Design and Testing VIII, 1081504 (5 November 2018);

Published in SPIE Proceedings Vol. 10815:
Optical Design and Testing VIII
Yongtian Wang; Tina E. Kidger; Kimio Tatsuno, Editor(s)