合成孔径雷达回波模拟器的建模仿真与系统设计

【作者】 黄延坤；

【导师】 贺知明；

【作者基本信息】 电子科技大学 ， 信号与信息处理， 2008， 硕士

【摘要】 合成孔径雷达成像技术作为一种新的雷达成像技术,现已广泛应用于军事和国民经济的许多领域中。随着SAR应用的日益广泛,许多诸如SAR系统设计、成像算法研究和评估、噪声和杂波抑制等场合对SAR原始回波数据有了更多的需要及更高的要求。本文对SAR原始回波数据的模拟及模拟器的设计进行了全面的研究,其主要内容如下:1.首先介绍了合成孔径雷达的高分辨力成像原理、SAR回波理论模型和几种SAR原始回波数据模拟算法。然后采用距离时域脉冲相干法对点目标的原始回波数据进行了模拟,并用经典RD算法对该回波进行处理,得到了期望的结果,本文还用同样的方法对点阵目标的原始回波数据进行了模拟。2.采用Kirchhoff近似理论和Franceschetti的地面场景仿真模型,并根据小平面单元与SAR之间的几何关系模拟出了分布目标的后向散射系数,进而利用二维频域快速傅氏变换法进行了分布目标原始回波数据的模拟,文中给出了分布目标原始回波数据模拟的具体步骤,最后分析了模拟得到的原始回波数据的特征。3.在介绍高斯海面模型的基础上,讨论了一种非高斯海面模型,这种海面考虑了海风引起的倾斜效果。然后在经典双尺度模型的基础上引入了修正双尺度模型,这样就考虑了海面在顺风和逆风方向散射的差异,同时还通过仿真分析了散射系数的幅值在不同极化方式和入射角下的变化情况。最后在静态场景的回波理论模型的基础上,给出了一种海面场景的回波生成方法,并通过仿真验证了该算法的正确性。4.提出了一种SAR回波模拟器的实现方式,主要包括该模拟器的工作原理和各组成模块的硬件设计,本人负责完成了原理图和PCB图的绘制。更多还原

【Abstract】 As a new imaging technology, Synthetic Aperture Radar (SAR) imaging technology has evolved to satisfy a variety of application for both civilian and military users. Along with the increasing and extensive application of SAR, many fields such as design of SAR system, evaluating of imaging algorithms, or suppression of noise and clutter ask for more demands and higher quality of SAR raw data.SAR raw data simulation and the design of simulator have been generally studied in this dissertation, the main contents of the dissertation are as follows:1. First of all, high resolution principle of SAR, SAR echo theoretical model and several algorithms of SAR raw data simulation are introduced. Then RTPC (Range Time domain Pulse Coherence) is adopted to simulate SAR point target raw data, which is processed by RD algorithm and anticipant result is presented, so is point array targets.2. Adopting the theory of Kirchhoff approach and facet model, backscatter coefficient of distributed target is computed. Then the raw data of distributed target based on 2D FFT is simulated. Steps of simulation is given and characteristics of raw data are also analyzed in this dissertation.3. Based on the introduction of Gaussian sea surface model, a non-Gaussian model is discussed, which is a skewed surface. Then a modified two-scale model is introduced to compute the backscatter coefficients, which accounts for up/down wind difference. The variation of backscatter coefficients’ amplitude along with polarization and incidence is analyzed. Finally a method of ocean surface raw data simulation is discussed, which is proved by simulation results.4. An implementation of SAR raw signal simulator is presented, including the function principle and hardware design of every part. Schematics and PCB layout are also carried out.更多还原