典型ISAR成像方法仿真研究

发布时间：2018-02-06 01:37

本文关键词： 逆合成孔径成像运动补偿弹道目标机动目标　出处：《电子科技大学》2014年硕士论文　论文类型：学位论文

【摘要】：逆合成孔径雷达(Inverse Synthetic Aperture Radar,ISAR)与合成孔径雷达(Synthetic Aperture Radar,SAR)成像原理相似,均利用大宽带信号实现距离向高分辨率,利用雷达与目标相对运动中不同散射点产生的不同多普勒差异实现方位向高分辨率,最终得到目标的二维高分辨率成像结果。ISAR主要针对如飞机、弹道导弹、轨道卫星等非合作空间目标进行成像,ISAR不同于光学成像,能够在任何气候、任何时间进行成像。除此外,ISAR通过处理接收到的目标回波去反演目标特征,从而实现重构目标中心分布,同时又能在窄带下探测目标位置、轨迹等额外信息,为目标识别提供有力途径。因此,ISAR成像技术在战场侦察、防御,卫星、天体观测等有极其重要的应用价值。本文主要对ISAR中以下几方面进行了详细研究,包括:ISAR转台成像原理,宽带雷达下目标回波信号分析与处理,ISAR运动补偿技术,成像聚焦算法等,其中运动补偿中的相位补偿部分在本文中重点进行了介绍。除详细推导了其理论原理与模型外,本文的工作重点是结合仿真与实测数据,验证论文算法以及提出的改进算法在工程应用中的有效性。文章所涉及的核心内容安排如下:(1)在简单介绍微波成像原理与目标散射机理的基础上、概述了ISAR成像基本概念、ISAR成像的应用领域,当前国内外ISAR成像研究现状及其研究的意义。(2)构建宽带回波信号模型,进而推导ISAR转台成像原理,分析了运动补偿对成像的必要性及如何实现方位向聚焦。距离对齐中分析了基于全局能量准则的对齐方法。(3)着重就ISAR运动补偿中的相位补偿以及时频成像技术进行了详细分析,并提出部分改进算法,相位补偿部分中基于离散多项式相位变换的自适应联合时频补偿,时频成像部分中引入了谐波小波变换。并利用点目标模型进行了仿真验证。(4)针对飞机目标和弹道中段目标进行了成像算法研究与仿真,将前面章节提出的算法应用至复杂真实的回波数据,以验证算法在工程应用上有效性,最后总结飞机与导弹目标成像方法上的区别。
[Abstract]:Inverse Synthetic Aperture Radarr (ISAR) is similar to synthetic Aperture Radar (SAR) imaging principle. Both use large wideband signals to achieve high range resolution. The high azimuth resolution can be achieved by using different Doppler differences produced by different scattering points in the relative motion of radar and target. Finally, the two-dimensional high-resolution imaging results of target .ISAR are mainly aimed at aircraft and ballistic missile. The imaging of non-cooperative space targets such as orbiting satellites is different from optical imaging and can be performed at any time in any climate. In addition, ISAR inverts the target characteristics by processing the received target echo. In order to reconstruct the center distribution of the target, and at the same time, it can detect the location and trajectory of the target in the narrow band, and provide a powerful way for target recognition. Therefore, ISAR imaging technology can be used in battlefield reconnaissance, defense, satellite, etc. In this paper, the following aspects of ISAR are studied in detail, including the imaging principle of the ISAR turntable, the analysis and processing of target echo signal under wideband radar, and the motion compensation technology of ISAR. The phase compensation of motion compensation is introduced in this paper. Besides the theoretical principle and model derived in detail, the emphasis of this paper is to combine the simulation data with the measured data. To verify the effectiveness of the proposed algorithm and the proposed improved algorithm in engineering applications. The core contents of this paper are arranged as follows: 1) on the basis of a brief introduction of microwave imaging principle and target scattering mechanism, In this paper, the basic concept of ISAR imaging and the application field of ISAR imaging are summarized. At present, the research status and significance of ISAR imaging at home and abroad are summarized. (2) the model of wideband echo signal is constructed, and the imaging principle of ISAR turntable is deduced. The necessity of motion compensation for imaging and how to realize azimuth focusing are analyzed. In range alignment, the alignment method based on global energy criterion is analyzed. An adaptive joint time-frequency compensation based on discrete polynomial phase transformation in phase compensation is proposed. In the part of time-frequency imaging, the harmonic wavelet transform is introduced, and the point target model is used to verify the simulation. The algorithm proposed in the previous chapter is applied to complex real echo data to verify the effectiveness of the algorithm in engineering applications. Finally, the differences between the imaging methods of aircraft and missile targets are summarized.
【学位授予单位】：电子科技大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TN957.52

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