机载SAR回波仿真与图像模拟

发布时间：2019-06-27 17:13

【摘要】：合成孔径雷达(SAR)具有高分辨等诸多优点,机载SAR回波仿真和图像模拟对于整个机载SAR系统的开发具有重要作用。机载SAR回波仿真和图像模拟是希望能够通过模拟的技术获得逼近真实的回波数据和图像,本文基于此点展开研究工作,全文的主要工作内容如下:(1)对SAR的合成孔径原理和它如何获得高分辨率的工作过程,和回波信号的特点进行了分析,以及如何通过回波信号得到SAR图像的成像过程进行了研究。(2)对SAR回波仿真方法进行了研究,以机载SAR回波仿真基本理论为出发点,在传统的时域仿真方法的基础上研究了一种快速时域仿真方法。针对时域仿真方法计算量大的缺点,频域回波仿真方法更能满足实时性的需求,研究了基于IωK回波仿真方法,对比传统频域仿真,能够模拟SAR的距离徙动,因此能够有更加精确的回波,最后,给出了点目标和面目标的时域仿真和基于IωK回波仿真的实验结果。(3)对航迹偏移下的SAR回波仿真和成像进行了研究,根据SAR的运动误差模型,分析了航迹偏移下的回波信号以及相位误差,导致了方位向的调频率估计误差,因此对有运动误差情况下运用MD算法方位向调频率估计展开了研究,最后给出了航迹偏移下的回波仿真以及用MD算法方位向调频率估计后的仿真成像结果。(4)根据参与项目的要求,对超宽带SAR信号展开了研究,超宽带信号能够使SAR获得更高的分辨率。首先对合成带宽技术进行了研究,通过发射步进频率信号采用合成带宽技术获得宽带信号,提高分辨率。另外为了降低采样率采用去斜率的方法降低带宽后进行处理,并对去斜率后的SAR分辨率和成像算法进行了研究,最后给出了合成带宽的仿真结果和去斜率后的信号及去斜率后的SAR成像仿真结果。综上所述,本文主要围绕以SAR回波仿真得到SAR模拟图像,研究了主要的回波仿真方法,以及航迹偏移情况下和超宽带信号下的回波仿真和成像研究。
[Abstract]:Synthetic Aperture Radar (SAR) has many advantages, such as high resolution and so on. Airborne SAR echo simulation and image simulation play an important role in the development of the whole airborne SAR system. Airborne SAR echo simulation and image simulation hope that the echo data and images can be approximated by simulation technology. based on this point, the main contents of this paper are as follows: (1) the synthetic aperture principle of SAR and how to obtain high resolution are analyzed, and the characteristics of echo signal are analyzed. And how to get SAR image imaging process from echo signal is studied. (2) the SAR echo simulation method is studied. Based on the basic theory of airborne SAR echo simulation, a fast time-domain simulation method is studied on the basis of the traditional time-domain simulation method. In order to solve the problem that the time domain simulation method has a large amount of computation, the frequency domain echo simulation method can better meet the real-time requirements. Compared with the traditional frequency domain simulation method, the frequency domain echo simulation method is studied. Compared with the traditional frequency domain simulation, it can simulate the range migration of SAR, so it can have a more accurate echo. The time domain simulation of point target and surface target and the experimental results based on I 蠅 K echo simulation are given. (3) the SAR echo simulation and imaging under track migration are studied. According to the motion error model of SAR, the echo signal and phase error under track migration are analyzed, which leads to the azimuth frequency modulation estimation error. Therefore, the azimuth modulation frequency estimation using MD algorithm is studied in the case of motion error. Finally, the echo simulation under track migration and the simulation imaging results after azimuth modulation frequency estimation with MD algorithm are given. (4) according to the requirements of the participating project, the ultra-broadband SAR signal is studied, and the ultra-broadband signal can make SAR obtain higher resolution. Firstly, the synthetic bandwidth technology is studied, and the broadband signal is obtained by transmitting the step frequency signal by using the synthetic bandwidth technology to improve the resolution. In addition, in order to reduce the sampling rate, the method of de-slope is used to reduce the bandwidth, and the SAR resolution and imaging algorithm after de-slope are studied. finally, the simulation results of synthetic bandwidth, the signal after de-slope and the simulation results of SAR imaging after de-slope are given. To sum up, this paper mainly focuses on the SAR simulation image obtained by SAR echo simulation, and studies the main echo simulation methods, as well as the echo simulation and imaging research under the condition of track offset and ultra-broadband signal.
【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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