| LIDAR is a product of technological development,and array LIDAR is widely used in the fields of unmanned driving,3D scanning modeling,meteorological environment detection and smart home Io T due to higher resolution and faster scanning speed.With the progress of laser technology and electronic technology,higher requirements are put forward for array lidar.Array lidar has to process signals and data in real time,requiring powerful computing capability and communication of the system,as well as reliable stability and accuracy.The array lidar gradually develops toward the goal of integration,low power consumption and high security.In this paper,we choose APD array working in Geiger mode as the photodetector of lidar,and carry out research on array lidar signal processing technology,design the hardware circuit and software system of array lidar,and test the system,the research content of this paper is mainly divided into the following aspects:(1)Research on the theory of array lidar.By summarizing the current situation of array lidar research at home and abroad and studying the relevant basic theories,the pulsed lidar ranging method is selected,the types of array lidar detectors and related characteristics are analyzed,the lidar distance equations under different targets are proposed,the system composition of array lidar is elaborated,and the relevant characteristic parameters of lidar are calculated.(2)Research on the front-end readout circuit of array lidar signal.The overall structure of the circuit is designed for the subject requirements,and the circuit bandwidth calculation is performed at the selected measurement range.The design of the front-end circuit is divided into three main parts,firstly,the stability and noise of the transimpedance amplification circuit is analyzed and studied,followed by the design of the secondary voltage amplification circuit and the moment identification circuit,and the bias regulator power supply is designed according to the operating requirements of the APD array detector,which is simulated by TI-TINA software,and the simulation results show that a 72 d B amplification gain is achieved in the bandwidth range of 70-88 MHz The simulation results show that the amplification gain of 72 d B is achieved in the bandwidth range of 70-88 MHz,and the weak signal with the input amplitude of 3.310-5A is discriminated,and the designed bias power supply meets the design requirements.The designed bias power supply satisfies the design requirements.The PCB design and circuit board are drawn using the Jalitron EDA circuit design software.(3)The time measurement system in array LIDAR was studied.The TDC time measurement technology is the core,the basic implementation form and measurement method of TDC measurement are studied,the performance of TDC is analyzed,and a suitable type of TDC chip is selected.The software system design is divided into four parts: Lab VIEW program design for the host computer,STM32 serial communication program design,STM32 and TDC communication program design and time measurement program design.(4)Build the experimental platform to analyze and verify the designed array LIDAR system.The designed hardware circuit is actually measured and compared with the circuit simulation results,and the circuit requirements are basically realized.The user login system is designed by using the upper computer Lab View,and the acquisition and transmission of LIDAR signals and display are realized by communicating with the serial port of STM32 lower computer. |
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