Laser pointing unit using tilting orthogonal double prisms (TODP) opens up a promising avenue for fine pointing in free-space laser communication, which can steer the laser beam with a pointing precision upon submicroradian order. How to obtain accurate inverse solutions is a basic issue for TODP systems. In this paper, a lookup-table method combined with the binary search procedure is demonstrated, and an iterative method that converges to the inverse solution by gradually reducing the search region is also investigated. The simulation results show that both methods can reach the pointing precision of micrometer order (namely submicroradian order after unit conversion) at a pointing distance of 400 mm, which can well meet the requirement of high-accuracy laser beam pointing applications.

中文翻译：

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亚微弧度激光指向中倾斜正交双棱镜的逆解研究

使用倾斜正交双棱镜（TODP）的激光指向单元为自由空间激光通信中的精细指向开辟了一条有前途的途径，它可以以亚微弧度级的指向精度引导激光束。如何获得准确的逆解是TODP系统的一个基本问题。在本文中，展示了结合二分搜索过程的查找表方法，并且还研究了通过逐渐减小搜索区域来收敛到逆解的迭代方法。仿真结果表明，两种方法在400 mm的指向距离上都可以达到微米级（即单位转换后的亚微弧度级）的指向精度，可以很好地满足高精度激光束指向应用的要求。