High-precision closed-loop tracking of moving targets based on rotational double prisms

Characterized by its compact structure and fast response, the rotational double prisms system is broadly applicable for high-precision pointing and tracking. In particular, closed-loop tracking technology based on an image detector can overcome beam deflection errors caused by prism parameter and target-guiding errors. However, the rotations of each prism affect beam deflection angles in both the x- and y-directions by different amounts in different areas. Therefore, aimed at this problem of the tracking error being coupled to the rotation angle of the two prisms, we proposed a real-time sector selection closed-loop tracking method by inputting error value feedback from the detector and outputting the adjustment values of the prisms. This method can simultaneously close-loop the error signal in two directions and is not limited by the target distance. We established a test platform to verify the proposed method. The test results showed that the proposed method can continuously track moving targets across different areas of a field of view for an extended period. When the maximum moving speed of the target was 0.32 deg /s, the root mean square tracking error of the noncentral area was <1 arcsec. The simulated and experimental results confirmed the effectiveness of this method. (C) 2021 Society of Photo-Optical Instrumentation Engineers (SPIE)

Automated summary

The rotational double prisms system is suitable for high-precision pointing and tracking due to its compact structure and fast response. A closed-loop tracking method based on image detector feedback was proposed to address the issue of tracking error coupled with prism rotation, providing effective tracking of moving targets across different areas of a field of view.