The Design On Phase-shift Laser Range Finder System

The laser ranging is a precision mearsurment technology along with the emergence andthe development of the laser technology.Because of its good accuracy characteristics,it iswidely used in lots of fields,such as the military field,the civil field,the aviation field,theindustry field and so on.Because of its high precision feature,the phase laser ranging is moresuitable for short distance mearsurement.Firstly, the paper simply introduces several methods of laser ranging,then focuses on thepriciple of phase laser ranging.On this basis,the paper put forward the overall design schemeand the overall design concept of the system is described. The program implements a10MHzlaser modulation to improve the precision of laser ranging.Secondly, the circuit design of the laser emission system is introduced.To achieve thepurpose of the stability of the laser singal emission, the paper discusses the choice of the laseremitting tube, the modulation of the light source, the design of the circuit section.Meanwhile, Photoelectric receiving circuit system is discussed and the subsystem circuitof the receiving part is also designed, including the reverse bias circuit, amplification andfilter circuit, frequency mixing circuit and digital phase detecting circuit. The receivingsystem use the Avalanche Photo Diode to receive the weak photoelectric signal and filter thenoise through a simple and effective method. In the end, a microcomputer is used to processthe results in the phase-detecting part.Lastly,some basic experiments and functional testing on the hardware of the system isdone and the test results are analyzed.The results show that the design of the system can meetthe requirements.At the end of the paper,a brief description of the system’s error is given andsome improvements is proposed.