摘要: |
机动平台大斜视SAR大场景成像时,加速度和大斜视角的存在使成像参数存在严重的二维空变性,极大限制了常规SAR成像方法的聚焦深度。为此,提出了基于多普勒域块处理的机动平台大斜视SAR成像方法。该方法通过子区域成像与全局数据块拼接,构建了高效的混合聚焦框架。在距离向处理中,对空变的距离徙动进行线性近似,并采用Keystone变换实现大场景的空变距离徙动校正;方位压缩时,进行子区域划分和多普勒域数据块的频域相位滤波处理,通过最小化局部多普勒参数差异实现高效空变补偿。理论分析和仿真结果表明,所提方法具有较高的运算效率,能够有效扩展成像场景的聚焦深度。 |
关键词: 机动平台,大斜视SAR,多普勒域块处理,频域相位滤波 |
DOI: |
分类号:TN957.52 |
基金项目:国家自然科学基金(No.62271163) |
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Doppler-domain Block Processing Based Imaging Method for Highly Squinted SAR Mounted on maneuvering platforms |
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Abstract: |
During large-scene imaging of highly squinted synthetic aperture radar (SAR) mounted on maneuvering platforms, the presence of acceleration and large squint angles introduces severe two-dimensional spatial variability in imaging parameters, significantly limiting the depth of focus of conventional SAR imaging methods. To address this, a Doppler-domain block processing-based imaging method for highly squinted SAR mounted on maneuvering platforms is proposed. This method constructs an efficient hybrid focusing framework by employing sub-region imaging and global data block stitching. In range processing, the linear approximation for the spatially variant range cell migration (RCM) is employed and the Keystone transform is utilized for large-scene spatially variant RCM correction. During azimuth compression, sub-region segmentation and frequency-domain phase filtering of Doppler domain data blocks are performed, minimizing the local Doppler parameter differences to achieve efficient spatially variant compensation. Theoretical analysis and simulation results demonstrate that the proposed method exhibits high computational efficiency and effectively extends the depth of focus for large imaging scenes. |
Key words: maneuvering platform highly squinted SAR Doppler-domain block processing frequency-domain phase filtering |