Research On Lidar High Precision Multi-time Multiplexing Ranging Technology

Lidar is a radar system that uses laser as an information carrier to detect target-related features.The laser radar emits laser light when it is working,and the laser light is reflected by the target to form an echo.The detector receives and processes the echo signal to obtain detection information,and then detects,tracks and recognizes the target to be measured.The development of lidar is very rapid.It is not only widely used in military detection and environmental measurement,but also widely used in the civilian market.Now it has become the focus of research in intelligent robots and unmanned driving.The existing lidar ranging systems on the market generally have the problem of low measurement accuracy.Therefore,designing a small and portable high-precision laser ranging system has important engineering application value.This article intends to develop a high-precision multi-line laser ranging device with a simple circuit structure through the research on the principle of multiple-time multiplexing laser ranging to provide technical support for the development of multi-line laser radar.This article first comprehensively analyzes the development status and existing problems of laser ranging systems at home and abroad,and compares the advantages and disadvantages of phase laser ranging and pulsed laser ranging.On this basis,the overall design scheme of the laser ranging system is proposed.Secondly,completed the laser ranging hardware circuit and related software design.Ranging hardware circuit mainly includes laser emission system,laser receiving system,time identification system and time interval measurement system.Among them,a narrow-pulse laser emission system is designed based on a semiconductor laser diode to achieve high-power,adjustable-frequency pulse laser output.The laser receiving system is designed with silicon-based avalanche diode(APD),and the high-speed Operational amplifier AD8009 is selected to amplify the photocurrent signal generated by the APD,and the amplifier circuit is simulated and analyzed.A transmitting and receiving control system based on TMS320F28335 is designed,and the time-sharing control of 16 channels of echo signals is realized through a multi-channel selection switch.Through comparison and analysis,a constant-proportion time discrimination circuit is built,and the time measurement chip TDC-GP2 is used to realize the single-channel multiplex time measurement of 16-channel laser ranging,thereby simplifying the overall circuit.The C language programming software completes data reading,TDC-GP2 management and other related operations,and realizes the collection and display of ranging signals.Finally,the distance measurement experiment platform was built,the accuracy test of the distance measurement system was completed and the measurement error of the system was calibrated.Experimental results show that the laser ranging system designed in this paper has an accuracy of 0.2m at 100m,which fulfills the high-precision design requirements of the laser ranging system.