穿墙成像雷达墙体杂波抑制技术研究

发布时间：2019-02-26 14:40

【摘要】：穿墙成像雷达利用电磁波的穿透特性,结合多种宽带信号和天线体制可对探测区域进行二维成像,不仅能够发现建筑物内的静止和运动目标,还能够对目标进行定位和跟踪,在军事、反恐、救灾等领域有着重要的应用价值。穿墙成像雷达发射的信号在穿透墙体的同时,大部分能量将直接返回,造成高瞬时功率的直达波信号;此外,部分信号在墙体介质内发生多次反射,形成持续时间较长的振铃干扰。以上墙体杂波严重干扰了对回波中相对微弱的目标信号的检测,研究如何消除墙体杂波,对提高穿墙成像雷达的性能具有重要意义。针对上述问题,本文首先分析了信号与墙体的作用机理,研究了穿墙成像的信号体制、收发模式、墙体杂波抑制原理等基本理论,通过处理仿真数据考察了不同收发模式下典型杂波抑制算法的有效性。在此基础上,研究了如何利用独立分量分析对直达波干扰进行抑制的问题,在回波域建立了算法模型,并针对采用多收多发模式时,因收发通道数量少而导致的观察信号不足问题,提出了一种采用单通道多次快拍数据建立观察矩阵,来分离直达波与目标信号的方法,仿真及实测数据处理结果表明,该方法可达到较好的直达波抑制效果。针对残余墙体杂波对目标信号的干扰问题,提出了基于稀疏盲解卷积算法的干扰抑制方法。引入了一般盲解卷积算法模型,重点分析了稀疏盲解卷积算法原理,讨论了残余回波的稀疏性及其量化方式。在此基础上研究了结合参数化建模与信号稀疏分解的稀疏盲解卷积算法,并针对全局参数优化方法的不足提出了局部优化的策略。最后通过仿真试验对比了不同算法的杂波抑制效果。
[Abstract]:Through-wall imaging radar makes use of the penetrating characteristics of electromagnetic waves, combined with a variety of broadband signals and antenna systems, can carry out two-dimensional imaging of the detection area, not only can find the static and moving targets in the building, but also can locate and track the targets. In the military, counter-terrorism, disaster relief and other fields have important application value. When the signal transmitted by the wall-penetrating imaging radar penetrates the wall, most of the energy will be returned directly, which will result in the direct wave signal with high instantaneous power. In addition, some signals are reflected in the wall medium many times, forming a longer duration of ringing interference. The above wall clutter seriously interferes with the detection of the relatively weak target signal in the echo. The research on how to eliminate the wall clutter is of great significance for improving the performance of the wall-penetrating imaging radar. In order to solve the above problems, this paper first analyzes the mechanism of the signal and the wall, studies the signal system of the wall-through imaging, the mode of receiving and receiving, the principle of the wall clutter suppression, and so on. The effectiveness of typical clutter suppression algorithms in different transceiver modes is investigated by processing simulation data. On this basis, the problem of how to suppress direct wave interference by independent component analysis is studied. The algorithm model is established in the echo domain, and the multi-receiving and multi-transmission mode is used to solve the problem. Due to the shortage of observation signals due to the small number of receiving and transmitting channels, this paper presents a method to separate direct wave from target signal by using single channel multi-shot data to set up observation matrix. Simulation and measured data processing results show that: 1. This method can achieve better direct wave suppression effect. Aiming at the interference of residual wall clutter on target signal, a new interference suppression method based on sparse blind deconvolution algorithm is proposed. The general blind deconvolution algorithm model is introduced. The principle of sparse blind deconvolution algorithm is analyzed. The sparsity of residual echo and its quantization method are discussed. On this basis, a sparse blind deconvolution algorithm combining parametric modeling and signal sparse decomposition is studied, and a local optimization strategy is proposed to overcome the shortcomings of the global parameter optimization method. Finally, the clutter suppression effects of different algorithms are compared by simulation experiments.
【学位授予单位】：国防科学技术大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TN957.52

【相似文献】