Pulsed Laser Ranging System Research

Aiming at present most of the laser range finder has shortcomings of system power consumption is relatively high, weak anti-interference ability, the measuring precision is not enough. Apply the digital technology has the advantage of strong anti-jamming capability, high precision, low power consumption, can make the performance of the laser range finder is greatly improved.In this paper, on the basis of the traditional pulse laser ranging system, by adding the echo signal analysis processing module in order to improve the measuring precision and scope of the whole system. A pulse laser ranging system can be divided into laser emission, laser receiving and echo signal processing three parts. Laser emission module with traditional laser ranging technique; Laser receiving module adopts high-speed A/D make the echo signal digital quickly; signal processing module adopts FPGA programming implementation, mainly to complete the sampling data caching and processing, as well as the whole clock control, logic control and sequential control of circuit.In addition, in terms of improving range performance, this paper mainly studied how to improve the pulse laser ranging accuracy and how to improve the laser ranging range from two aspects of content. In terms of improve the ranging accuracy, from the counting method, this paper adopts800MHz pulse counting high frequency. Mainly studied based on the FPGA implementation of firing pulse and high frequency counting unit. In the aspect of improving distance measuring range, from the receiving system of digital, this paper puts forward the sampling rate of250MHz of high-speed A/D converter and the FPGA composed of digital receiving system, after the transformation of digital signal processing related algorithms, by improving the signal-to-noise ratio, achieve the goal of improving distance measuring rang.This article finally completed the whole system hardware circuit design. Using software programming to achieve the clock control module, pulse generating module, data caching module, timing module, and other functions. Algorithm realized using Haar wavelet transform domain LMS adaptive filtering of the echo signal filtering de-noising and using wavelet singularity detection principle of echo signal peak detection. Using MATLAB and DSP Builder, Quartus II and modelsim tool, completed the LMS adaptive filtering algorithm is implement in FPGA. And in terms of range performance meet the requirement of the system parameters.