Design And Implementation Of High-precision Parallel Ranging Module For Linear Array Lidar

Linear array scanning imaging lidar is the core sensor of autonomous driving vehicle applications.Improving the detection performance of ranging module is an effective way to enhance the overall detection performance of linear array-based lidar system.In this paper,a multi-channel ranging module with high precision performance has been designed and researched,which aims to satisfy the overall detection requirements of linear array-based scanning lidar system utilized on self-driving car platform.The detection precision simulation model of linear array-based lidar system has been built based on the traditional lidar detection theory.The impact of the detection precision of the ranging module on the total detection precision of lidar system has been analyzed under the condition that the design parameters of lidar system front-end module have been determined.The simulation results provide the theoretical basis for the parameter optimization of ranging module;The requirement analysis of ranging module has been analyzed according to the linear lidar system detection performance.And the principle and error sources of commonly utilized laser pulse TOF(time of flight)measurement technology have been compared and analyzed.The 12-channel parallel distance measurement module,including hardware and software,has been realized based on digital chips like TDC-GPX and etc.The detection performance of the designed ranging module has been corrected based high precision time interval measurement platform,and compared with reference datasheet.The error factors that affect the detection performance of the ranging module have been discussed.Experimental results have showed that the ranging module achieves the performance that resolution is better than 73ps,precision is better than 1 10ps,and the measurement absolute error is less than 700ps in 0-2μs.The influence of ambient temperature and power supply voltage on the performance of designed ranging module has been analyzed.The circuit for detecting performance stability of the ranging module has been designed.And the high and low temperature experiments verified its effectiveness.The detection performance of linear array-based scanning lidar system has been analyzed.It showed that the ranging resolution of the linear lidar system is better than 2.5cm,and the fitting distance error of each channel is less than 5cm.In the range of 10-100m,the total system precision is consistent with the numerical simulation results.It has verified that the detection precision of the system is than 10cm in whole 100m range,and better than 5cm in R<50m.Combining the linear array-based lidar system with high-speed scanning platform to conduct a 3D imaging experiment for three kinds of typical environments.The results showed that the imaging resolution of lidar system can reach 2000pixe1×12pixel.and the frame rate is more than 5Hz.The imaging results,with rich environment information and obvious target features,provide the probability to realize high precision environment reconstruction,robot road planning and navigation.