摘要
高分辨成像处理以及运动目标的检测与成像是合成孔径雷达研究的核心内容,也是合成孔径雷达重要的研究和发展方向。本文的主要工作集中在合成孔径雷达成像算法研究,合成孔径雷达高分辨成像处理,以及运动目标的检测与成像处理三个方面。
论文首先简要介绍了合成孔径雷达的基本工作原理,建立点目标雷达回波模型。在此基础上,讨论了合成孔径雷达距离多普勒成像算法以及Chirp-Scaling成像算法,分析了各自的特点,对两种成像算法进行了计算机仿真实验以及实际数据实验验证。
合成孔径雷达实现几何高分辨成像处理的关键之一是进行运动补偿和聚焦处理来补偿各种原因引起的相位误差。本文研究了合成孔径雷达三种自聚焦算法,子孔径自聚焦算法、相位梯度自聚焦算法以及对比度最优自聚焦算法,分析了三种聚焦算法的原理和特点,同时对聚焦成像算法进行了计算机仿真以及实际数据实验验证。
如何提高辐射分辨是获得高分辨合成孔径雷达图像的另一个关键问题。本文讨论了与合成孔径雷达辐射分辨特性相关的问题,相干斑噪声的产生机理以及多视处理方法克服相干斑噪声的原理。文中还对实际合成孔径观测数据进行多视处理实验分析。
运动目标检测和成像是合成孔径雷达一个十分重要的发展方向。本文在前人工作的基础上,提出了一种新的基于分数傅立叶变换的运动目标检测和成像算法,在对该算法进行理论分析的基础上,给出了计算机仿真实验以及基于实际数据的运动目标检测和成像结果。实验证明该方法是一种有效的运动目标检测与成像算法,能够方便的在现有的系统中实现,具有的实用化潜力。
Synthetic Aperture Radar high resolution imaging, moving targets detection and imaging are key issues in the research field of Synthetic Aperture Radar. The dissertation focuses on three aspects, that is, Synthetic Aperture Radar imaging algorithms, Synthetic Aperture Radar high resolution imaging, moving targets detection and imaging.
Firstly, the fundamentals of Synthetic Aperture Radar have been briefly introduced and the radar return signal of point target has been constructed. Two common-used Synthetic Aperture Radar imaging algorithms, Range-Doppler algorithm and Chirp-Scaling algorithm, have been analyzed and tested using compute simulation and real Synthetic Aperture Radar data.
One key issue of the Synthetic Aperture Radar high resolution imaging is how to obtain SAR image of high geometrical resolution. The phase error reduction using motion compensation and autofocus algorithms are the essential steps in Synthetic Aperture Radar high resolution imaging. The dissertation analysis the three autofocus algorithms, namely, Map Drift autofocus algorithm. Phase Gradient Autofocus algorithm and Contrast Optimization autofocus algorithm. Meanwhile, the computer simulation and the real Synthetic Aperture Radar data are used to test these algorithms.
The other key issue of the Synthetic Aperture Radar high resolution imaging is how to obtain SAR image of high radiometric resolution. The dissertation discusses some related issues on SAR radiometric resolution, the fundamentals of speckle noise and the suppression of speckle noise using multilook processing. The real Synthetic Aperture Radar data experiment demonstrates the effectiveness of multilook processing.
Moving targets detection and imaging is also an important research trend of Synthetic Aperture Radar. Based on the analysis of previous research work, a novel
moving targets detection and imaging method using fractional Fourier has been proposed in this dissertation. Its technical background has been analyzed carefully and its feasibility and effectiveness are supported by the computer simulation and the real Synthetic Aperture Radar data experiment. In addition, it is easy to be implemented in the SAR system, which enhances its potential for practical application.
引文
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