With the improvement of SAR resolution, super-resolution SAR imaging is more and more widely used in the all-time and all-weather video surveillance and remote sensing imaging. One implementation of super-resolution SAR is that radar works in the spotlight mode. In the case with highly squinted angle and acceleration, the azimuth space variance and the coupling between range and azimuth will become serious in super-resolution imaging. Thus, an azimuth frequency nonlinear chirp scaling algorithm is proposed to solve this problem. Based on the acceleration model, the accurate 2-D spectrum is performed by adopting the method of series reversion. The space-variance of missile-borne SAR in curved flight path is analyzed and an azimuth polynomial phase filter is constructed to make the coefficients of the perturbation function has sufficient flexibility to eliminate the spatial-variant couple terms between range and azimuth. In addition, the gradient operation is used to expand the space-variant coefficients of azimuth modulation term, and the perturbation function is applied to eliminate the space-variant in azimuth direction. The proposed focusing method can process the missile-borne SAR data obtained in spotlight mode in highly squinted angle with high efficiency. The simulation results verify the effectiveness of the proposed imaging approach. The integration of the research in this paper and the deep learning will further pave the way of super-resolution SAR imaging applications in disaster monitoring, security and surveillance.

中文翻译：

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一种新的曲线轨迹超分辨率合成孔径雷达AFNCS算法

随着SAR分辨率的提高，超分辨率SAR成像越来越广泛地应用于全天候、全天候的视频监控和遥感成像。超分辨率SAR的一种实现方式是雷达工作在聚光灯模式。在斜角和加速度较大的情况下，超分辨成像中的方位角空间方差和距离与方位角之间的耦合会变得严重。因此，提出了一种方位频率非线性线性调频缩放算法来解决这个问题。在加速度模型的基础上，采用级数反演的方法得到精确的二维谱。分析了弹载SAR在弯曲飞行路径下的空间方差，构造了方位多项式相位滤波器，使微扰函数的系数具有足够的灵活性，以消除距离和方位之间的空间变化耦合项。此外，利用梯度运算扩展方位角调制项的空间变异系数，应用微扰函数消除方位角方向的空间变异系数。所提出的聚焦方法可以高效处理聚束模式下大斜角下的弹载SAR数据。仿真结果验证了所提出的成像方法的有效性。