基于互相关分析的激光自准直小角度测量技术(英文)

Laser Autocollimation Measurement of Small Angle Based on Cross Correlation

应用光学自准直原理,选用激光二极管(LD)为光源,位置敏感探测器(PSD)为光电探测器,构建了一种基于互相关分析的激光自准直小角度测量系统.为了提高小角度测量精度,该系统对光源进行正弦调制,利用互相关分析解调出待测小角度信息.根据互相关分析理论,设计了信号处理系统,对影响系统精度的主要因素进行了分析.实现了测量样机,并进行了性能测试实验.实验表明,互相关解调系统有效地抑制了噪声的影响,样机具有较高的二维小角度测量精度和示值稳定性,在±150″范围内,最大非线性误差为0.6″,重复性误差为0.2″,漂移为0.4″/4h.

A laser autocollimation measurement system based on optical autocollimation principle was put forward for small angle measurement,using laser diode（LD）as light source and position sensitive detector（PSD）as a laser spot detector.In order to improve the precision,the small angle measurement system adopted cross correlation analysis to modulate LD with sine-wave.Through cross correlation demodulation,the small angle to be measured was then extracted from the output of PSD.The signal processing system for small angle demodulation was designed and some factors influencing the accuracy were discussed.Finally,this paper gave a prototype of laser autocollimation measurement system and its performance tests.The prototype shows high precision and stability for 2-D small angle measurement,with the maximum nonlinear error of 0.6″,the repeatability error of 0.2″ and the drift of 0.4″/4 h within the range of ±150″.