Research On Single Photon Lidar Ranging System Modulated By Pseudorandom Noise Code

Lidar ranging has excellent performance such as long detection distance,high measurement accuracy and short detection period,which has been widely used in military,space technology,auto autonomous driving and many other fields.The signal-to-noise ratio of lidar system,detection range and accuracy can be improved by using pseudorandom noise(PN)code modulation and single photon detection technology.In this paper,FPGA is used to generate high-frequency pseudo-random code modulated laser,and a single photon lidar ranging system is designed.The main research contents of this article are as follows:(1)Based on the lidar equation,the range model,the principle of PN code and the single photon detection technology,the principle of the single photon lidar system modulated by PN code is proposed.And the feasibility of this scheme is theoretically analyzed,which provides a basis for the parameter calculation and hardware design of the system.(2)The single photon lidar system modulated by PN code is simulated by using MATLAB,mainly includes the relationship between the lidar operating distance and optical parameters such as transmitting power,receiving power and average reflectance of target.And it also includes the generation of PN code,echo signal processing,the calculation of correlation and distance information extraction.The simulation results prove that the single photon lidar system modulated by PN code meets the performance requirements.(3)The single photon lidar system modulated by PN code is based on Xilinx's Artix-7series FPGA as the main control unit and Verilog language for software design.Software design mainly includes the design of PN code generation module,the design of SFP optical module,the design of correlation calculation module and the design of serial port module.The Simulation curves of each module are given and the results are analyzed.Simulationresults show that the system software design meets performance requirements.(4)For the lidar system,the analysis and design of the hardware principle are carried out,mainly including the design of the bias voltage circuit,the design of temperature control circuit and the design of gated quenching circuit.Finally,the principle prototype test is carried out.The test results show that this design scheme meets the requirements of distance measurement in terms of detection distance,measurement error and data update rate.