曲线弹道SAR RD-Dechirp快视成像算法

RD-Dechirp algorithm for curvilinear trajectory SAR quick look imaging

研究了以景象匹配制导为目的的曲线弹道合成孔径雷达(synthetic aperture radar,SAR)快视成像问题。首先建立了曲线弹道SAR回波信号模型,分析了多普勒历程和距离徙动特点,提出了等效正侧视成像的概念,并分析了等效条件,大大减小了距离徙动校正难度和回波信号距离向与方位向的耦合,然后推导了曲线弹道SAR回波信号的二维频谱表达式,在此基础上提出了结合距离-多普勒算法和频谱分析(spectral analysis,SPECAN)的快视成像方法。所提算法使用高效的SPECAN方法进行方位压缩,能够完成曲线弹道SAR部分孔径数据的精确相干处理,没有因为孔径的非直线而增加成像算法的复杂性。

The problem of curvilinear trajectory synthetic aperture radar （SAR） quick look imaging for ap- plication in image matching guidance is addressed. The echo signal model of curvilinear trajectory SAR is built first, followed by an analysis of the characteristics of Doppler history and range migration. The concept of equivalent broadside imaging for curvilinear trajectory SAR is presented and its equivalent condition is also ana- lyzed, which can significantly reduce the difficulty of range migration correction and the coupling between range and azimuth. Then two dimensional spectrum of the echo is derived. On this basis, the quick look imaging algo- rithm combining range Doppler algorithm and spectral analysis （SPECAN） is proposed. The efficient SPECAN method for azimuth compression is used and the proposed algorithm is capable of processing the partial aperture data of curvilinear trajectory SAR coherently and accurately. Besides, the computational complexity is not in- creased though the aperture is non-linear.