【摘要】 针对高分辨宽测绘带合成孔径雷达(Synthetic Aperture Radar, SAR)由斜视角空变引起的多普勒参数空变进而导致的成像性能下降的问题,提出新的多普勒参数空变解析式并给出改进的频域非线性变标(Frequency Non-Linear Chirp Scaling, FNLCS)算法。算法通过线性距离走动校正(Linear Range Walk Correction, LRWC)和梯形变换(Keystone Transform, KT)降低了回波的距离-多普勒耦合,并构建了用于描述多普勒参数空变特性的距离方位频域模型,以此重新求解FNLCS算法的均衡函数和压缩函数。仿真结果表明,所提模型和算法能有效处理SAR回波的多普勒参数空变问题,获得更好的成像效果。更多还原

【Abstract】 The spatial-variant squint angle produces spatial variant Doppler parameters and further degrades the image quality when focusing high-resolution wide-swath synthetic aperture radar(SAR) data. To circumvent this issue, an improved Frequency Non-Linear Chirp Scaling(FNLCS) algorithm based on an innovative analytical expression of Doppler parameters is proposed. Firstly, a linear range walk correction(LRWC) and a Keystone transform(KT) are adopted to mitigate the range-Doppler coupling. Then, a new range-azimuth model in the frequency is derived to depict the spatial-variant properties of Doppler parameters. Finally, the equalization factors of FNLCS algorithm and the compression function are resolved. Simulation results are presented to validate the effectiveness of the proposed algorithm.更多还原