针对目前定心仪精度不高、并依赖于人眼的现状，提出一种基于PSD的高精度定心仪研究方法。采用自准直光路形式和位置敏感探测器PSD对经过被测目标返回的光斑实行定位，并通过读取计算机上的坐标值来判断是否达到准确的定心。文中对定心仪的光学系统进行设计，并运用神经网络的训练来校正PSD的非线性，在测量范围±2 mm~±500 mm内定心精度达到1 μm的设计要求。

Against the current situation of centering instrument with low precision and dependent on the human eyes, a research method of high-precision centering instrument based on position-sensitive detector (PSD) was put forward. Through the use of self-collimated optical path and PSD, the return light spot from the target was located, and the coordinate value on the computer was read to judge whether the accurately centering was achieved. The design of the centering instrument optical system and the nonlinear correction of PSD by neural network training were carried out. Results show that t can achieve the design requirement of centering accuracy with measuring range of ±2 mm~±500 mm, which is much better than traditional centering instruments.