一种多普勒域走动校正的斜视SAR成像算法

为了解决时域校正走动带来的方位空变性问题，提出了一种在方位多普勒域走动校正的斜视合成孔径雷达（SAR）成像算法。文中利用级数反演理论，将斜距公式展开至三次项，推导出SAR回波信号的两维频谱表达式。再从两维频谱出发，提出了基于两维频谱匹配滤波的斜视SAR成像算法。该算法考虑到距离空变性问题，提出先在两维频域进行走动校正和相位预滤波，接着在距离多普勒域进行线性频率变标的处理方法，经过距离脉压和方位脉压能够得到聚焦良好的SAR图像。此外，该方法与距离徙动（RMA）算法相比可以有效地降低需要处理的数据量。最后，临近空间SAR仿真实验证明本文提出方法的可行性和有效性。

A Squint SAR Imaging Algorithm for Linear Range Cell Migration Correction in Doppler Domain

The Linear range cell migration correction in time domain will bring about space variability in the azimuth. In this paper, a squint Synthetic aperture radar (SAR) imaging algorithm is proposed to solve the problem brought by the linear range cell migration correction in time domain, where the linear range cell migration component is corrected in azimuth Doppler domain. In this new imaging algorithm, the slant-range formula is expanded to cubic, and then the two-dimensional spectrum expression is derived by using series reversion. After that, the squint SAR imaging algorithm is proposed based on two-dimensional spectrum matched filter. This algorithm takes into account the problem of space variability in the range. At the first, the linear range cell migration correction and the pre-filter is made in the two-dimensional frequency domain, and then the algorithm of linear chirp-scaling is operated in time domain in range and frequency domain in azimuth. Finally, a well focused SAR image can be obtained after pulse pressure in two-dimensional frequency. Compared to the Range Migration Algorithm (RMA), the proposed algorithm can effectively reduce the amount of data be processed in the imaging processing. By processing the near space SAR simulation data, the effectiveness of this algorithm is proved.