Research On Anti-interference Laser Ranging System Based On CDMA

In order to improve anti-interference ability of laser ranging system, enhance reliability of measurement under complicated environment condition, this paper proposes a anti-interference algorithm of frequency-hopping modulation based on CDMA, uses FPGA as the core technology to design a laser ranging system which is small size, high reliability.The research contents of this paper include analysis of anti-interference theory of laser ranging system based on CDMA and design for software and hardware.Firstly, from traditional theory of laser ranging, it analyses theories and merits and drawbacks of several kinds of ranging methods, and analyses the reason influences the reliability of laser ranging system;then, it is based on frequency-hopping technology to analyze features of several kinds of pseudo-random code, it chooses Gold code with good self-correlation and mutual-correlation to build the model of anti-interference ranging system based on frequency-hopping technology, then it completes design for overall solution of laser ranging system based on CDMA and system testing with reference to hardware requirement. This paper uses Verilog HDL to realize module designs for pseudo-random code generator, frequency-hopping modulator, threshold detection; the hardware designs of ranging system includes laser emission, echo receiving, FPGA processing.This paper accomplishes designs and debugging of system hardware circuit, designs and simulation of FPGA modules, tests the ranging system and analyzes the anti-interference performance of it, then analyzes and evaluates experimental data and error. Experimental results show that functions of software and hardware for this system can realize, it can achieve the accurate ranging results even in the complicated environments with light-disturbance. Namely, the laser ranging system based on CDMA proposed by this paper has a better anti-interference ability, meet the requirement of subject research.