Study Of A Phase-shift Laser Ranging System

The phase laser ranging system is a universal non-contact measuring method,which uses lasers with high brightness and good directionality and combines with high-sensitivity photodetectors for high-accuracy distance measurement.According to the principle of phase laser ranging,the accuracy of the modulation frequency and the accuracy of the phase discrimination directly determine the accuracy of the phase laser ranging system.Therefore,improving the accuracy of the frequency and phase discrimination of the modulated signal is a crucial part of this paper.Based on the analysis of the phase-based laser ranging system at home and abroad in recent years,this paper summarizes their respective advantages and their related parameters,and clarifies the research significance and application prospect of laser ranging system.Combined with the basic principles of laser ranging system,the paper introduces,analyzes and compares various different methods of laser ranging system.At the same time,it also analyzes and compares the phase identification methods of many different methods,which provides a theoretical basis for the phase laser ranging system scheme adopted in the following text;Next,the overall system structure of the phase laser ranging system is analyzed and introduced.A novel modulation method is proposed,which uses the IIC timing protocol written by FPGA to configure the clock generator inside the Si5351 chip to gain two modulation signals.The frequencies of the two modulated signals are 2.5 MHz and 150 MHz respectively.Compared with the DDS module,the modulated signal is simple,flexible,and small in size and low in power consumption,facilitating integration of the overall system.According to the sequence of the structural flow of the system,the design principle and working mode of each module are sequentially performed,and the detailed design of the hardware circuit is performed.The phase discrimination mode is combined with the phase identification method of the spectrum analysis method.The algorithm and program of the phase laser ranging system are written.Finally,the stability and ranging accuracy of the phase laser ranging system are tested.At the same time,in the case of different time intervals,the system repeatedly performs single measurement and continuous measurement.Experimental results show that the measurement error of the phase laser ranging system is positive and negative 5 mm within 0-40 m and the mean square error is 3mm.