合成孔径雷达成像及自聚焦算法研究

【作者】 李磊；

【导师】 宋耀良；

【作者基本信息】 南京理工大学 ， 信号与信息处理， 2009， 硕士

【摘要】 本文主要研究了合成孔径雷达成像算法和雷达成像自聚焦算法两个方面的内容。在对合成孔径雷达成像算法的研究中,实现了距离多普勒算法和距离徙动算法。采用距离多普勒算法对多点目标分别在窄带和超宽带条件下进行成像,成像结果表明距离多普勒算法在窄带条件下能够得到高质量的目标二维图像,而在超宽带条件下成像质量较差。对于距离徙动算法,着重讨论了算法中的两个关键步骤:参考函数相乘和STOLT插值,并通过计算机仿真对多点目标进行了成像。和距离多普勒算法相比,该算法在处理超宽带信号方面更具有优越性。在对合成孔径雷达成像自聚焦算法的研究中,首先研究了相位梯度自聚焦算法,该算法对仿真数据取得了比较好的聚焦效果。针对传统自聚焦算法中存在的一些问题,本文将遗传算法应用于合成孔径雷达成像自聚焦,并根据雷达回波信号和雷达成像的特点对遗传算法进行了改进,由此提出了遗传自聚焦算法,并将这种新算法应用于实际合成孔径雷达回波数据中,得到了很好的成像结果。更多还原

【Abstract】 Synthetic aperture radar imaging algorithm and radar imaging autofocus algorithm are mainly discussed in this thesis.In the research on the SAR imaging algorithm, range Doppler algorithm and range migration algorithm are implemented. Range Doppler algorithms of multipoint targets could be adopted in the SAR imaging of the narrow and ultra-wide band signals respectively. The image shows that range Doppler algorithm could obtain high quality two-dimensional image in narrow band condition but worse quality in Ultra-wide band condition. For the Range Migration Algorithm, its two major steps, reference function multiplication and STOLT interpolation, have been mainly discussed. And the multipoint target imaging is simulated. Compared with the former R-D algorithm, R-D Migration algorithm has the superiority in processing of the Ultra-wide band signals.In the research on SAR imaging autofocus algorithm, the phase gradient autofocus algorithm is discussed firstly which achieves a better focusing effect using simulated data. According to problems of the traditional autofocus algorithms, the thesis introduces the Genetic Algorithm (GA) to SAR imaging autofocus and makes some improvements in accordance with the characteristics of the radar echo signal and imaging processing. Therefore, the Genetic Autofocus Algorithm is presented and has been applied to the SAR radar echo data with excellent imaging characteristics.更多还原