Full-area three-element Risley prism system based on high precision real-time continuous scanning strategy

For a high precision and real-time full-area continuous Risley Prism system, the main factors impacting scanning accuracy are blind zones, computation time, and system accuracy. Considering wedge thickness and the spacing between wedges, this paper proposes a three-element Risley Prism system to obtain precise scanning points. In the model, the inverse solution can be obtained using the damped least squares method. Meanwhile, the initial values are optimized through an approximate analytical model to enhance computational efficiency. Additionally, a system spacing proportional coefficient is introduced to significantly minimize blind zones. A numerical method is adopted to further reduce nonlinear errors to approach theoretical values. Simulations demonstrate that the iteration count of the proposed method is reduced from 7 to 1, the solution time decreased from 10 s to 1.5 s, and the blind spot range decreased from 79 um to 0.664 nm. In addition, experimental results further confirm the model's capability for continuous, real-time, and high-precision scanning across the entire area.