Research On LiDAR Ranging Technology Based On Full Waveform

At present,in military,industrial,medical and other aspects,multi-line lidar has a wide range of applications.In order to meet the needs of the laboratory to develop high-precision lidar,this paper has conducted in-depth research on multi-channel time interval measurement system and time identification system.This article describes the actual situation of digital time conversion technology and time identification technology and the progress of scholars’ research.Using the existing laboratory resource platform,a high-precision multi-channel modular TDC(Time-to-Digital Converter)based on FPGA is designed.Analyze the implementation principle of the multi-phase clock sampling structure,and rely on the clock management module to form a multi-channel fixed phase shift clock,which greatly simplifies the circuit design and effectively reduces resource consumption.Based on FPGA design principles,the hardware modules are divided.The results are as follows:gating signal,multi-phase clock generation unit,latch sampling unit,edge preprocessing and buffer unit,and edge time detection unit.Secondly,the development of time identification technology was investigated,and a time identification system based on full waveform was designed.According to functional modules,the system can be divided into three components:peak holder,variable threshold circuit and three-channel TDC timing unit.Eventually,a time discrimination system and a three-channel TDC timing system were implemented on the XC7Z010-1CLG400C model FPGA.In order to verify the performance of the realized TDC and the moment identification module,the construction of the test system is implemented,based on this experiment and test.Experiments show that the resolution of TDC reaches 156 picoseconds,the measurement accuracy is equivalent to 62 picoseconds,the DNL is between-0.16-0.21 LSB,the INL is less than 0.5LSB,and it has good linearity.The realized full waveform time discrimination system,combined with TDC for time measurement,can control the ranging error to about ± 3.5cm,achieving a high-precision ranging effect,and having good practical value.