基于Keystone变换和扰动重采样的机动平台大斜视SAR成像方法

加速度和下降速度的存在使机动平台大斜视SAR的成像参数存在明显的2维空变性，严重影响场景的聚焦深度。针对这个问题，该文提出了一种基于Keystone变换和扰动重采样的机动SAR成像方法。首先，通过距离走动校正和去加速处理实现距离方位解耦以及方位频谱去混叠，然后采用方位时域的Keystone变换校正空变的距离徙动；在方位压缩过程中，通过引入时域的高阶扰动因子去除多普勒参数的2阶及3阶方位空变性，然后通过方位频域的重采样处理去除多普勒参数的方位1阶空变性。所提方法能够有效校正距离徙动轨迹和方位聚焦参数的2维空变性，实现机动平台大斜SAR的大场景成像，仿真分析验证了所提方法的有效性。

Maneuvering Platform High-squint SAR Imaging Method Based on Keystone Transform and Perturbation Resampling

The existence of acceleration and descent velocity makes the imaging parameters of high-squint SAR mounted on maneuvering platform have obvious two-dimensional spatial variability, which affects seriously the focus depth of the scene. To solve this problem, a maneuvering SAR imaging method based on Keystone transform and azimuth perturbation resampling is proposed. First of all, the range azimuth decoupling and the azimuth spectrum de Aliasing are realized by the range walk correction and de-acceleration processing. Then the spatial-variant range cell migration is corrected by the Keystone transform in the azimuth time domain; In the process of azimuth compression, the second- and third-order spatial variabilities of Doppler parameters are removed by introducing the high-order perturbation factor in the time domain, and then the first-order spatial variability of the Doppler parameters is removed by the azimuth resampling processing in the azimuth frequency domain. The proposed method can effectively correct the two-dimensional spatial variability of range cell migration trajectory and azimuth focus parameters, and realize the large scene imaging of high-squint maneuvering SAR. Simulation analysis verifies the effectiveness of the proposed method.