中文摘要：

为了实现对微小位置信号的精密测量,建立了PSD位置检测系统。对该系统的光强调制方法、测量原理、位置测量算法及误差评估进行了研究。实验发现当信号光强微弱时,位置敏感器件（PSD）受背景光强影响很大。采用正弦调制光强,通过带通放大的方式,克服背景光强的影响,极大地提高了测量系统的信噪比。针对所提取的PSD光强差与和信号均为调制频率信号,且幅值与相差由光斑位置决定的特点,提出应用同步A/D与椭圆拟合法计算光斑位置的方法,并对相关计算公式进行了理论推导。实验结果表明：在测量范围达到9 mm的条件下,测量精度可达到0.01 mm.基本满足PSD位置检测方法的稳定可靠、测量精度高、抗干扰能力强等要求。

英文摘要：

In order to realize the precision measurement of weak position signal,position detection of position sensitive detector（PSD）was set up.PSD is influenced by the background light source when the weak light falls on its photosensitive face.It applied the technique of sine light intensity modulation and band-pass filter which can overcome the background light to enhance the signal to noise ratio（S/N）of this position detection system greatly.The sum-intensity signal and the difference-intensity signal extracted from PSD are modulation frequency signals and the amplitude ratio and phase discrepancy are decided by the position of the light spot.Based on these characteristics,the method by using simultaneous A/D and elliptical algorithm to locate the light spot was adopted,and related theoretical formulas were also carried out.When the range of measured position is within 9 mm,the measurement accuracy may be up to 0.01 mm.It can satisfy the system requirements of non-contact,online,real time,higher precision and rapid speed,as well as strong anti-jamming and stabilization.