Research And Implementation Of Phase Laser Ranging Technology

Ranging technology based on laser ranging has been widely used in the fields of unmanned aerial vehicle,unmanned aerial vehicle power line inspection,3D laser scanning and 3D real scene map in recent years.Therefore,the study of laser ranging methods,ranging means and testing accuracy has positive significance.At present,the commonly used laser ranging methods are pulse laser ranging,triangle laser ranging,feedback laser ranging,interferometric laser ranging and phase laser ranging.Due to the high accuracy of phase laser ranging,therefore,the phase laser ranging is deeply studied and analyzed in this paper.The main methods of phase laser ranging are as follows:(1)transmitting and receiving signals are sampled directly by high speed A/D converter,then the phase difference of transmitting and receiving signals can be calculated by digital signal processing,and the actual distance can be obtained indirectly.(2)the transmitted and received signals are converted into low-frequency signals after mixing,and then the distance measurement is realized by pulse counting;or the signals obtained by mixing are directly sampled in real time and the distance measurement is realized by the way of method one.Method one is that the frequency of the laser signal can't be too high because of the limitation of the working frequency of the A/D converter,so it can't meet the practical application of some occasions.In the second method,the frequency of the signal is reduced by mixing.However,the relative error of ranging is inversely proportional to the frequency after mixing.Therefore,too low frequency will greatly reduce the accuracy of the test.For this reason,we combine the advantages of method one and method two.Using mixing technique,FFT technique,a phase laser rangingmethod based on sequential equivalent sampling is proposed.The test method is analyzed theoretically and the test error is simulated.Finally,the realization scheme based on FPGA and DSP technology is designed.Through the actual test of the hardware system,the actual test results are basically consistent with the theoretical simulation results,and good results have been obtained.