Establishment and verification of formulas of target tracking based on dual liquid crystal polarization gratings

In this paper, the relationship between miss distance, target position, and rotation angle of dual liquid crystal polarization gratings (LCPGs) is proposed for the first time, a target tracking system based on the rotating dual LCPGs is established, and a closed-loop target tracking process based on the formula is described. We establish the optical structure of the dual LCPGs, and the simulation compares the difference between the altitude and azimuth angles of the target position from the formula and the ZEMAX simulation. In the simulation validation, we also compare and analyze the proposed formula with the formula for vertical incidence to illustrate the necessity to introduce miss distance. We assemble a target coarse tracking device and perform the tracking experiment using the proposed formula to test the coarse tracking accuracy of the system. The coarse tracking accuracy and the angle information we obtained from simulation and experiment meet our proposed technical specification of no more than 0.45mrad, showing that the proposed formula provides a good basis for stable target coarse tracking and is instructive for engineering applications.