Design Of Laser Echo Data Acquisition And Transmission System Based On FPGA

Because the analog circuit used in traditional laser rangefinders has poor resistance to external interference,it is easy to cause missed detection and false alarms in harsh environments,and it has many components,large volume and weight,and cannot further improve the signal-to-noise ratio of the signal to filter out the peak value of the echo signal.In view of the above-mentioned shortcomings,this paper proposes a method of processing laser echoes by digital method.The advantages of digital technology are used to improve the performance of traditional laser ranging system.The digital design of the laser rangefinder under the condition of small size and light weight realizes the reconstruction of the signal by increasing the echo signal-to-noise ratio at a long distance to achieve the purpose of increasing the ranging range.This paper designs a data acquisition system with ADC and FPGA as the control core for the purpose of improving the weak signal-to-noise ratio of laser echo during long-distance measurement.In this system,the ADC samples the weak echo signal and performs fast digital processing,FPGA Logic control of the entire system and FIFO buffering and accumulating average processing of digitized data.The principles of laser distance,working distance and signal-to-noise ratio equations are evaluated and studied,and the technology required for the data acquisition system of weak echo signals is introduced in detail,including A/D conversion,Digital cumulative averaging,logic control,signal processing and transmission technology.The linear cumulative average algorithm used in this paper has been simulated by Matlab software to prove its performance.The result shows that the signal is accumulated M times,and the echo signal-to-noise ratio can be improved by √M times.Verilog HDL is used for Quartus II programming design for each module of the data acquisition system designed in this paper,and Model Sim software is used to verify the logic function of the system.Finally,the platform was built for the experiment.In order to achieve a more accurate location of the echo signal,a median filter with a window of 5 was used to process the echo signal.Finally,the experimental results proved the linear accumulation used by the system.The averaging algorithm can improve the echo signal-to-noise ratio to achieve the purpose of increasing the range,and the error is within 1.4m.