基于频域插值的大角度俯冲弹载SAR成像方法  

A Large-Angle Dive Missile-Borne SAR Imaging Method Based on Frequency Domain Interpolation

作　　者：刘昌捷 郭苹 吴富恩 张梦琪 唐世阳[2] LIU Changjie;GUO Ping;WU Fuen;ZHANG Mengqi;TANG Shiyang(Xi’an Key Laboratory of Network Convergence Communication,Xi’an University of Science and Technology,Xi’an 710054,China;National Key Laboratory of Radar Signal Processing,Xidian University,Xi’an 710071,China)

机构地区：[1]西安科技大学西安市网络融合通信重点实验室,西安710054 [2]西安电子科技大学雷达信号处理全国重点实验室,西安710071

出　　处：《空军工程大学学报》2023年第4期56-61,共6页Journal of Air Force Engineering University

基　　金：国家自然科学基金(61701393,61971329);陕西省重点研发计划(2020ZDLGY02-08);空间微波技术国家级重点实验室开放基金课题(HTKJ2022KL504019)。

摘　　要：弹载合成孔径雷达(SAR)在大角度俯冲运动阶段,由于其复杂的飞行特性,回波信号存在严重的耦合性和空变性,这将导致传统的聚焦算法失效。针对这一问题,提出了一种改进的极坐标格式(PFA)频域成像算法。首先建立大角度俯冲弹载SAR的斜距模型,并对距离历程进行泰勒级数展开,然后利用级数反演法推导高精度的回波二维频谱。在二维频域,将高阶交叉耦合项进行二维分解,并在此基础上推导出新的频域二维插值映射函数,极大提升了聚焦成像的效果。相对于传统PFA,文中算法更适用于大角度俯冲弹载SAR,并通过仿真实验验证了其有效性。Aimed at the problems that as for missile-borne SAR at a large-angle dive movement stage,the echo signal has serious coupling and space-variance due to its complex flight characteristics to make the traditional focusing algorithm invalid,an improved frequency domain imaging algorithm of polar format algorithm(PFA)is proposed.Firstly,a range model of large-angle dive missile-borne SAR is established,and the range history is expanded in Taylor series.And then the high-precision two-dimensional spectrum of echo is derived by the series inversion method.Finally,the high-order cross-coupling terms are decomposed in the two-dimensional frequency domain.Moreover,a new two-dimensional interpolation mapping function is derived,greatly improving the performance of focused image.Compared with traditional PFA,the proposed algorithm is more suitable for large-angle dive missile-borne SAR,and is valid.

关 键 词：弹载合成孔径雷达 大角度俯冲 级数反演 极坐标格式算法 

分 类 号：TN957.52[电子电信—信号与信息处理]