机载SAR多模式统一化成像处理技术研究

合成孔径雷达(SAR)技术能够实现感兴趣区域(ROI)的多模式成像与超高分辨观测。然而，超高分辨成像因多脉冲长时间相干积累而面临方位频谱混叠问题，且对于斜视情况下的凝视和滑动聚束模式，传统频域成像算法难以实现统一化处理。据此，本文提出了一种SAR多模式统一化成像处理算法。首先，采用线性距离走动校正削弱斜视数据的两维耦合。然后，结合基于方位Deramp技术的混叠频谱重建方法与方位重采样，实现混叠信号的恢复及聚焦深度问题的解决。最后，利用扩展的距离徙动算法进一步完成ROI精聚焦。本文所提算法能够对斜视的凝视和滑动聚束数据进行统一化的成像处理。基于点目标仿真与机载SAR多模式实测数据处理结果，验证了所提方法的有效性。

Research on Multi-Mode Unified Processing Technology for

Multi-mode imaging and ultra-high resolution observation of region of interest (ROI) can be realized by synthetic aperture radar (SAR) technology. Nevertheless, due to the long coherent integration time of multiple pulses, ultra-high resolution imaging faces the issue of aliasing azimuth spectrum. In terms of the squint staring and sliding spotlight modes, the traditional frequency-domain imaging algorithm is difficult to achieve the unified processing. Accordingly, a multi-mode unified algorithm for SAR imaging processing is proposed in this paper. First, the linear range walk correction is employed to mitigate the two-dimensional coupling of squint SAR data. Then, the issues of aliasing signal and depth of focus are solved by using the spectrum reconstruction approach based on the azimuth Deramp technology and azimuth resampling. Finally, the extended range migration algorithm is exploited to further complete the fine ROI focusing. The proposed algorithm can process the squint staring and sliding spotlight data in a unified manner. Based on the point target simulation and multi-mode airborne SAR data processing results, the effectiveness of the proposed method has been verified.