基于改进PFA的车载大斜视SAR成像算法  

Automotive High Squint SAR Imaging Algorithm Based on Improved PFA

作　　者：王佳慧 刘衍琦 王纪平 金秋 毛新华 WANG Jiahui;LIU Yanqi;WANG Jiping;JIN Qiu;MAO Xinhua(Key Laboratory of Radar Imaging and Microwave Photonics,Ministry of Education,College of Electronic and Information Engineering,Nanjing University of Aeronautics and Astronautics,Nanjing 211106,China)

机构地区：[1]南京航空航天大学电子信息工程学院雷达成像与微波光子技术教育部重点实验室,江苏南京211106

出　　处：《雷达科学与技术》2023年第4期411-419,共9页Radar Science and Technology

基　　金：国家自然科学基金(No.62071225);航空科学基金(No.2020Z017052001);江苏省自然科学基金(No.BK20211181)。

摘　　要：为了应对车载毫米波雷达大斜视成像困难的问题,本文提出一种改进的极坐标格式算法(Polar Format Algorithm,PFA)对条带车载毫米波雷达斜视回波进行基于子孔径拼接的成像。该算法从条带数据与聚束数据的特点出发,将全孔径回波划分为子孔径,利用PFA处理子孔径数据。由于PFA存在波前弯曲误差,子图像不能直接拼接,因此对每一幅子图像进行几何失真校正。同时,以重叠子孔径的划分方式保证成像结果的高分辨率。最后截取子图像进行拼接得到条带SAR成像结果。所提方法解决了车载毫米波雷达大斜视情况下两维耦合严重的问题。通过对点目标和实测数据的仿真与分析验证了所提方法的有效性。This paper proposes an improved polar format algorithm(PFA),which is used to process the high squint stripmap automotive millimeter wave radar echoes.Based on the characteristics of stripmap data and spotlight da⁃ta,the full⁃aperture is divided into sub⁃apertures,and the sub⁃apertures are processed by PFA.Due to the wavefront bending error,sub⁃images cannot be mosaicked directly,so geometric distortion correction is carried out for each sub⁃aperture.The high resolution is ensured by overlapped sub⁃apertures.Finally,sub⁃images are intercepted for mosaicking to obtain stripmap SAR imaging result.The algorithm solves the severe problem of two⁃dimensional coupling in high squint imaging of stripmap SAR.Simulation and processing of the point targets and the measured data demonstrate the effectiveness of the proposed method.

关 键 词：车载毫米波雷达斜视SAR 子孔径划分 极坐标格式算法 重叠子孔径 子图像拼接 

分 类 号：TN959[电子电信—信号与信息处理]