发布时间 : 星期四 文章基于Ka波段安防LFMCW雷达信号处理的研究 - 图文更新完毕开始阅读
摘要
摘 要
相较于摄像头，雷达拥有较大优势，包括白天黑夜均能探测远距离的目标，且不受雾、云和雨的阻挡，具有全天候、全天时的特点，并有一定的穿透能力。因此，雷达也在安防领域的热门应用方向。目前，安防雷达广泛应用于周界监控、机场安全区保护、监狱安防、输油管道和油田保护以及与现有的安防视频系统融合使用。
安防雷达一般采用LFMCW（线性调频连续波）体制。LFMCW雷达拥有较好的距离和速度分辨率、可靠性高、距离盲区小以及良好的抗干扰性能等优点。因此在雷达测距、测速系统中得到广泛应用。
本论文就是在Ka波段安防雷达项目的基础上，研究了LFMCW雷达的基带信号处理算法，主要的研究工作有：
首先介绍了LFMCW雷达研究背景以及现状，具体分析了LFMCW雷达的基本原理和信号模型，阐述了LFMCW雷达优缺点，以及Ka波段LFMCW安防雷达系统设计要求，并提出基带信号处理方案。重点研究了LFMCW雷达信号处理中几种重要模块，包括动目标指示（MTI）、动目标检测（MTD）、恒虚警（CFAR）处理、以及多目标配对。各个模块均利用MATLAB实现多种不同算法仿真并对比性能。其中在动目标指示（MTI）部分，用遗传算法设计了自适应MTI滤波器，采用了创新的适应度函数和惩罚函数，最终所设计出来的滤波器性能良好。动目标检测（MTD）部分对比了基于FFT以及FIR的两种MTD滤波器算法。恒虚警（CFAR）部分分别分析对比一维二维场景下多种恒虚警处理算法。多目标配对部分分别对比了频域配对法、MTD频域配对法、变周期法以及加平坦斜率法。随后，基于以上工作整合了各个算法模块完成LFMCW雷达系统仿真，并最终验证系统仿真结果正确。
最后负责了雷达整机基带部分的外场测试，介绍了雷达整机测得的结果，同时将外场采集得到的数据导入MATLAB软件以验证在实际情况下所仿真的系统的可靠性，对比了两个场景下外场数据仿真的效果。最后的结果表明雷达整机可以良好的实现测量多目标的速度和距离参数，所研究的算法可以较好的满足项目指标。
关键词：线性调频连续波雷达、动目标检测、恒虚警处理、多目标配对、外场测
试
I
Abstract
ABSTRACT
Compared to the camera, radar has more advantages. For example, it can detect distant targets day and night without being influenced by fog, clouds, and rains, which means that it has the capability of all-weather and all-time, and the ability to penetrate. Therefore, radar application is also popular in the field of security. Currently, the security perimeter surveillance radar is widely used in airport security zone detection, protection of pipelines and oil fields, as well as integration with the existing prison security video system.
Security radars generally use LFMCW (Linear Frequency Modulated Continuous Wave) system. LFMCW radar has a good distance and speed resolution, high reliability, small blind distance and good anti-jamming performance. So it is widely used in radar range and velocity measurement.
This thesis is based on Ka-band radar project on security, studied some LFMCW radar baseband signal processing algorithms. The main research work is as follows:
First, introduced the background and current research situation of LFMCW radar, followed by a detailed analysis of its basic principles and signal model. Also, the advantages and disadvantages of LFMCW radar were introduced. Based on the above research and the specific requirements of Ka-band security radar, the baseband signal processing solution was proposed, among which several important radar signal processing modules were mainly studied, including moving target indicator (MTI), moving target detection (MTD), constant false alarm rate (CFAR) processing, and multi-target pairing. Simulations using MATLAB were done for each module in order to compare the performances of different algorithms. In MTI part, an adaptive novel MTI filter has been designed by applying Genetic Algorithm. In the process, an innovative fitness function and penalty function are used, and the simulation result shows that the designed filter has good performance. In MTD part, the paper compared two different kinds of filter designing algorithm based on FFT and FIR. As for CFAR processing, various one-dimensional two-dimensional scene processing algorithms were analyzed and compared. In multi-target pairing section, four algorithms are introduced: pairing method in frequency domain, MTD-pairing method in frequency domain, variable cycle method, and the method of adding a flat slope. Subsequently, completed the integration of the various algorithm modules and the
II
Abstract
simulation of the whole LFMCW radar system, and verified the simulation results.
Another work that has been done is the field testing of the whole radar system. At the same time, two sets of data collected from different outfields was imported into the software MATLAB to verify the reliability of the actual performance of the simulated system. The final results show that the whole system works well, and it has achieved the measurement of multi-target speed and distance parameters.
Keywords: Linear Frequency Modulated Continuous Wave radar, Moving Target Detection, CFAR processing, Multi-target pairing, Field test
III
目录
目 录
第一章 绪论 .............................................................................................................. VII
1.1 LFMCW的主要优缺点 .................................................................................. 1 1.2 LFMCW雷达研究状况与发展动态 .............................................................. 2
1.2.1历史概况 ................................................................................................ 2 1.2.2当前发展动态 ........................................................................................ 3 1.3论文背景及任务需求 ...................................................................................... 3 1.4论文内容安排 .................................................................................................. 4 第二章 Ka波段LFMCW安防雷达系统设计描述 ................................................... 5
2.1 LFMCW雷达的基本原理 .............................................................................. 5 2.2 LFMCW雷达信号分析 .................................................................................. 8 2.3 毫米波LFMCW雷达的优点 ...................................................................... 11 2.4 Ka波段LFMCW安防雷达系统设计要求 .................................................. 11
2.4.1 信号处理系统功能 ............................................................................. 12 2.4.2 信号处理系统参数 ............................................................................. 12 2.4.3 信号处理系统实现方案 ..................................................................... 13 2.5 本章小结 ....................................................................................................... 13 第三章 LFMCW雷达信号处理算法分析 ............................................................... 14
3.1 动目标显示（MTI） .................................................................................... 14
3.1.1杂波模型分析 ...................................................................................... 14 3.1.2 MTI改善因子（If） ........................................................................... 15 3.1.3 传统MTI滤波器设计 ........................................................................ 17 3.1.4 自适应MTI滤波器设计 .................................................................... 19
3.1.4.1 遗传算法（GA）简介 ............................................................. 19 3.1.4.2 使用遗传算法（GA）设计自适应MTI滤波器 .................... 20 3.1.4.3 自适应MTI滤波器仿真实例 .................................................. 22
3.2 动目标检测（MTD） .................................................................................. 24
3.2.1 基于FFT的MTD滤波器组 ............................................................. 25 3.2.2 FIR实现MTD滤波器组 .................................................................... 27 3.3 恒虚警（CFAR）检测技术 ......................................................................... 28
3.3.1 引言 ..................................................................................................... 28
IV