An Improved Phase Detection Method for Laser Guide Systems Using Position Sensitive Detectors

In this article, an improved phase detection method is proposed for laser guide systems using position sensitive detectors. The key of the method is the detection of phase differences. To deal with the nonmonotonic output behavior, a phase shift process is introduced instead of complicated hardware implementation in conventional methods. Moreover, the phase shift process moves the measurement zone of relatively large measurement error to the zone of small error. Compared with the conventional methods, the phase shift process requires fewer modules and connections and reduces measurement error, whereas the parallel phase comparison design provides a higher sensitivity. The experimental results show the effectiveness for measurement error and sensitivity of the proposed method.