复杂背景超宽带穿墙雷达成像研究

发布时间：2018-06-21 07:20

本文选题：超宽带穿墙雷达 + 杂波抑制　；参考：《南京信息工程大学》2017年硕士论文

【摘要】：超宽带穿墙探测技术是近年来新兴的一种非侵入式探测技术,利用电磁波信号穿透非金属障碍物并对目标进行探测及成像。由于其较强的穿透能力以及较高的距离分辨率,超宽带穿墙探测技术被广泛地应用于军用和民用领域。在超宽带穿墙雷达的应用中,目标信号通常会淹没于墙体杂波信号之中,无法进行目标检测及成像。此外,利用倾斜天线阵列接收的回波信号进行墙体后场景图像的重建,同样影响目标定位的准确性。针对上述问题,本文的主要内容包括:(1)研究了现有的基于熵值的墙体杂波抑制算法,该算法存在门限可调范围受限,且需要对成像区域进行多次扫描等问题。基于扩展信源熵值理论,本文提出了一种改进的墙体杂波抑制算法。与现有算法相比,在测量方式相同的情况下,本文算法的杂波抑制效果更优,同时能够在保证成像效果的前提下减少天线扫描次数,降低了穿墙成像雷达的复杂度。(2)讨论了由于天线扫描轨迹或天线阵列倾斜于墙体而造成的目标成像错位和畸变的问题。现有的文献中,穿墙雷达成像模型通常假设天线紧贴墙体或平行于墙体放置。然而,在实际应用中无法保证这一前提。研究表明天线扫描轨迹或天线阵列与墙体之间存在的未知倾角,会导致现有算法失效,即成像图中目标会发生错位和畸变,影响目标检测及定位的精度。针对该问题,本文基于电磁波逆时传播原理提出一种基准面校正算法,并且通过实验证明了该算法能够有效地消除未知倾角造成的影响。
[Abstract]:Ultra-Wideband Wall Detection (UWB) is a new non-invasive detection technique in recent years, which uses electromagnetic wave signal to penetrate non-metallic obstacles and to detect and image targets. Because of its strong penetration ability and high range resolution, UWB wall detection technology has been widely used in military and civil fields. In the application of UWB wall-penetrating radar, the target signal is usually submerged in the wall-clutter signal, so the target detection and imaging can not be carried out. In addition, the echo signal received by tilted antenna array is used to reconstruct the scene image behind the wall, which also affects the accuracy of target location. Aiming at the above problems, the main contents of this paper include: 1) the existing entropy based wall clutter suppression algorithm is studied. The threshold range is limited and the imaging region needs to be scanned several times. Based on the extended source entropy theory, an improved wall clutter suppression algorithm is proposed in this paper. Compared with the existing algorithms, the clutter suppression effect of this algorithm is better than that of the existing algorithms, and it can reduce the number of antenna scans under the premise of ensuring the imaging effect. In this paper, the complexity of wall-penetrating imaging radar is reduced. (2) the problem of target imaging dislocation and distortion caused by antenna scanning track or antenna array tilting to the wall is discussed. In the existing literature, the radar imaging model usually assumes that the antenna is placed close to or parallel to the wall. However, this premise cannot be guaranteed in practical application. The results show that the scanning trajectory or the unknown inclination between the antenna array and the wall will lead to the failure of the existing algorithms, that is, the target will be mislocated and distorted in the imaging map, which will affect the accuracy of target detection and location. In order to solve this problem, a datum correction algorithm based on the principle of electromagnetic inverse time propagation is proposed, and it is proved by experiments that the algorithm can effectively eliminate the influence caused by unknown inclination angle.
【学位授予单位】：南京信息工程大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TN957.52

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