基于CDMA的抗干扰激光测距系统的研究

发布时间：2018-11-22 09:10

【摘要】：为了提高激光测距系统抗杂光干扰的性能,改善多系统联合测试或存在其他激光脉冲信号的背景环境下系统测量的可靠性,本文提出一种基于CDMA的跳频调制扰算法,并以FPGA技术为核心,设计了一套体积小,可靠性高的激光测距系统。本文的研究内容为基于CDMA的激光测距系统抗干扰原理分析以及测距系统软件和硬件部分的设计。首先,从传统的激光测距原理出发,系统分析了几种常见测距方法的原理和优缺点,并对影响激光测距系统可靠性的原因进行了分析；然后,以跳频技术为基础,分析了几种常见伪随机码的特性,选用自互相关性好的Gold码为跳频码,建立基于跳频技术的抗干扰测距系统模型,并结合硬件要求完成基于CDMA的激光测距系统的整体方案设计和系统测试。测距系统软件部分采用Verilog HDL语言编程实现伪随机码生成器,跳频调制器,门限检测,测距计数器等模块的设计；硬件部分选取合适的芯片完成激光发射,回波接收,FPGA处理三部分电路的设计。本文完成了FPGA各功能模块的软件设计与仿真以及硬件电路的设计和调试,并对测距系统进行了实际的测试和抗干扰性能的分析,对实验数据和实验误差进行了分析和评估。实验结果表明,该系统各部分的功能均己实现,在多个系统联合测试或存在其他激光脉冲信号干扰的情况下也可获得准确的测量结果,即本文提出的基于CDMA的激光测距系统具有更好的抗干扰能力,达到了课题研究的要求。
[Abstract]:In order to improve the performance of laser ranging system against clutter interference and improve the reliability of system measurement under the background environment of multi-system joint testing or other laser pulse signals, a frequency-hopping modulation and scrambling algorithm based on CDMA is proposed in this paper. A laser ranging system with small volume and high reliability is designed based on FPGA technology. The research content of this paper is the analysis of anti-jamming principle of laser ranging system based on CDMA, and the design of software and hardware of ranging system. Firstly, based on the traditional laser ranging principle, the principles, advantages and disadvantages of several common ranging methods are systematically analyzed, and the reasons that affect the reliability of laser ranging system are analyzed. Then, based on the frequency hopping technology, the characteristics of several common pseudorandom codes are analyzed. The frequency hopping codes are selected as the Gold codes with good autocorrelation, and the anti-jamming ranging system model based on the frequency hopping technology is established. The overall scheme design and system test of laser ranging system based on CDMA are completed in combination with hardware requirements. In the software part of the ranging system, the pseudorandom code generator, frequency hopping modulator, threshold detection, ranging counter and other modules are designed by using Verilog HDL language. In the hardware part, the appropriate chip is selected to complete the design of laser emission, echo receiving and FPGA processing circuit. In this paper, the software design and simulation of each functional module of FPGA and the design and debugging of hardware circuit are completed, and the actual test and anti-jamming performance of the ranging system are carried out, and the experimental data and experimental error are analyzed and evaluated. The experimental results show that the functions of each part of the system have been realized, and the accurate measurement results can be obtained in the case of the joint testing of multiple systems or the presence of other laser pulse signal interference. That is to say, the laser ranging system based on CDMA has better anti-jamming capability and meets the requirements of the research.
【学位授予单位】：西安工业大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TN248

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