根据位敏探测器的理想定位模型及其信号处理方式，建立了位敏探测器位移测量误差的数学模型,以获得高准确度的位移测量.所建模型显示系统的测量误差随光斑强度增大而减小，随电噪音增大而增大.为了验证理论模型的正确性，以单颗红外发光二级管作为靶标光源，用枕型位敏探测器及其测试电路板在暗室中搭建了实验系统，分别在9组不同光斑强度下对21个位置点进行位移测量实验，相邻两位置点的间距为0.3 mm.使用MATLAB的CFTOOL工具对每组测得位移值进行拟合，以均方根误差作为准确度的评价指标，结果表明: 位移实验的准确度值与模型计算的准确度值基本符合，准确度随光斑强度变化的趋势完全一致.

In order to obtain high-precision displacement measurement, a mathematical model for measurement deviation was constructed according to the ideal position model and signal processing methods of position sensitive detector. It indicated that the measurement deviation of system decreased with the increase of the light spot intensity, while increased with the increase of the electrical noise. A displacement measurement experiment was designed to verify the model. The experimental system included an infrared light-emitting diode and a pillow type position sensitive detector and its test circuit board. Displacement measurement experiments of 21 position points were carried out in nine different groups of spot intensities separately. The distance between every two position points each was 0.3 mm. Each group of displacement measurement data was fitted by using MATLAB CFTOOL tool, with root mean square error as a parameter evaluating the precision of position sensitive detector displacement measurement. The result shown that the precision value and its variation trends in the displacement experiment are consistent with that of model calculation.