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A traditional tracking device obtain the attitude angle by analyzing the spots position on photodetector. However, the attainable angular measurement accuracy depends on the field of view (FOV), number of pixels of the photodetector and the centroiding algorithm. In this paper, we present a high-precision attitude angle measuring system based on Talbot interferometry using cross-gratings and four wedge plates, which can acquire the real-time change of incident angle along two axis. The specific structure of the system is introduced, and the formula for calculating the relative angle is derived. The tracking accuracy is analyzed to be better than 0.2 arcsecond, which is dependent on the grating period, the distance between the two gratings and the gray scale of image. The Simulation results show that the RMS error of relative angle is better than 0.1 arcsecond both in x and y direction.
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