多通道SAR高分辨率成像及动目标检测技术研究

发布时间：2018-06-07 22:47

本文选题：SAR + 高分辨率　；参考：《电子科技大学》2014年硕士论文

【摘要】：相比于单通道合成孔径雷达(SAR)系统,多通道系统因增加了接收通道而使回波数据有了冗余,系统自由度增加,能够获取目标丰富的细节信息,更精准地从背景杂波和噪声中区分出目标,适用于高分辨率成像和目标检测技术研究。多通道系统具有数据利用率高、系统成本低、灵活性强等优势,本文以此为背景,将宽带合成技术和动目标检测方法同时应用到多通道SAR系统中,研究了基于宽带合成的距离向高分辨率成像技术和中心频率步进的多通道SAR动目标检测方法,所做的具体工作及创新如下:1、首先介绍了宽带合成技术,说明了距离向分辨率的原理和通道数与距离向分辨率的关系;然后结合两种经典的多通道SAR动目标检测技术分析了多通道SAR系统用于动目标检测中的优势和存在的问题。2、研究了基于误差补偿的频域宽带合成方法。首先,建立了多通道SAR回波信号模型。然后,介绍了一种典型的频域宽带合成方法:针对该方法中同等效相位中心合成带来的传输路径误差,结合仿真实验分析了其对宽带合成的影响,并给出误差补偿方法;针对该方法中通道不一致带来的幅相误差,结合仿真实验分析了其对宽带合成的影响,并给出误差补偿方法;尤其针对该方法中的子带重叠误差提出一种频域滚降滤波法,详细给出了算法原理及处理步骤,并结合仿真实验论证了该误差补偿方法的有效性。最后,针对这种典型的频域宽带合成方法存在的这三种误差,采用上述补偿方法,获得了距离向高分辨率的SAR图像,验证了基于误差补偿的频域宽带合成方法的有效性。3、提出了图像域的宽带合成方法。针对传统的宽带合成技术存在的运算量大、实时性差的问题,本文提出基于图像域的宽带合成方法:首先,介绍了图像域宽带合成算法的基本思路,推导并建立了算法模型;然后,给出了算法步骤和框图;最后,从理论上说明了在SAR图像分辨率相当的情况下,所提的图像域宽带合成方法较传统的宽带合成方法在运算量和实时性方面有明显的优势。4、研究了中心频率步进的三通道ATI动目标检测及重定位技术。首先研究了偏置相位中心天线(DPCA)和沿迹干涉(ATI)两种SAR动目标检测方法,对比说明了ATI在动目标检测方面有更好的检测性能和抗干扰特性;然后,针对传统的两通道ATI无法提取动目标参数的问题,重点研究了中心频率步进的三通道ATI动目标检测技术,并通过提取动目标的相位信息,进而估计目标的多普勒参数和运动参数,实现对动目标的检测和重定位。
[Abstract]:Compared with single channel synthetic Aperture Radar (SAR) system, the multi-channel system increases the echo data redundancy, increases the degree of freedom of the system, and can obtain the rich detailed information of the target. It is more accurate to distinguish targets from background clutter and noise, and is suitable for high resolution imaging and target detection. Multi-channel system has the advantages of high data utilization, low system cost and strong flexibility. In this paper, wideband synthesis technology and moving target detection method are applied to multi-channel SAR system at the same time. The range high resolution imaging technology based on wideband synthesis and the multi-channel SAR moving target detection method based on step by step of center frequency are studied. The specific work and innovation are as follows: 1. Firstly, broadband synthesis technology is introduced. The principle of the range resolution and the relationship between the number of channels and the range resolution are explained. Then, the advantages and problems of moving target detection in multi-channel SAR system are analyzed with two classical multi-channel SAR moving target detection techniques, and the wideband synthesis method in frequency domain based on error compensation is studied. Firstly, the multi-channel SAR echo signal model is established. Then, a typical broadband synthesis method in frequency domain is introduced. Aiming at the transmission path error caused by the same equivalent phase center synthesis in this method, the influence of the method on broadband synthesis is analyzed in combination with the simulation experiment, and the error compensation method is given. Aiming at the amplitude-phase error caused by channel inconsistency in this method, this paper analyzes its influence on wideband synthesis and gives an error compensation method combined with simulation experiments, especially, a frequency-domain rolling filtering method is proposed for the overlapping error of sub-band in this method. The principle and processing steps of the algorithm are given in detail, and the effectiveness of the error compensation method is demonstrated by simulation experiments. Finally, aiming at the three errors of this typical broadband synthesis method in frequency domain, the range high-resolution SAR images are obtained by using the compensation method mentioned above. The effectiveness of the frequency domain wideband synthesis method based on error compensation is verified. 3. A wideband synthesis method in image domain is proposed. Aiming at the problems of large computation and poor real-time performance in traditional wideband synthesis technology, a wideband synthesis method based on image domain is proposed in this paper. Firstly, the basic idea of wideband synthesis algorithm in image domain is introduced, and the algorithm model is derived and established. Then, the algorithm steps and block diagrams are given. Finally, it is theoretically explained that the resolution of SAR images is the same as that of SAR images. Compared with the traditional wideband synthesis method, the proposed wideband synthesis method has obvious advantages in computation and real time performance. A three-channel ATI moving target detection and relocating technique with center frequency step is studied in this paper. In this paper, two kinds of SAR moving target detection methods, DPCA (offset phase center antenna) and ATI (interference along track), are studied. The comparison shows that ATI has better detection performance and anti-jamming performance in moving target detection. In order to solve the problem that traditional two-channel ATI can not extract moving target parameters, a three-channel ATI moving target detection technique with center frequency stepping is studied, and the phase information of moving target is extracted. Then the Doppler parameters and motion parameters of the target are estimated to detect and relocate the moving target.
【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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