圆迹SAR的建筑物全方位优化成像方法研究

Circular SAR Optimization Imaging Method of Buildings

圆迹SAR(Circular SAR,CSAR)可对目标进行全方位观测,获取目标的完整散射信息,该文提出一种相干与非相干处理相结合的圆迹SAR建筑物全方位优化成像方法。利用FEKO建立建筑物的电磁散射模型来模拟雷达回波进行成像,并与散射各向同性情况下的成像结果分析比较,得出对建筑物CSAR成像最佳方位相干累积角度大小。由于实际场景中建筑物的散射方向未知,将CSAR的360°回波数据划分为小角度重叠的多个子孔径并分别成像,对成像后的子孔径进行非相干融合后得到全方位合成图像。再对合成后图像进行极化目标分解,获取场景中建筑物的轮廓信息。P波段机载圆迹SAR数据处理结果表明该方法优于传统全相干累积方法,可实现建筑物的全方位轮廓信息提取。

The Circular Synthetic Aperture Radar（CSAR） can obtain the entire scattering properties of targets because of its great ability of 360° observation. In this study, an optimal orientation of the CSAR imaging algorithm of buildings is proposed by applying a combination of coherent and incoherent processing techniques.FEKO software is used to construct the electromagnetic scattering modes and simulate the radar echo. The FEKO imaging results are compared with the isotropic scattering results. On comparison, the optimal azimuth coherent accumulation angle of CSAR imaging of buildings is obtained. Practically, the scattering directions of buildings are unknown; therefore, we divide the 360° echo of CSAR into many overlapped and few angle echoes corresponding to the sub-aperture and then perform an imaging procedure on each sub-aperture. Sub-aperture imaging results are applied to obtain the all-around image using incoherent fusion techniques. The polarimetry decomposition method is used to decompose the all-around image and further retrieve the edge information of buildings successfully. The proposed method is validated with P-band airborne CSAR data from Sichuan,China.