一般构型机载双站大斜视SAR二维Chirp-Z变换成像算法  

Two-Dimensional Chirp-Z Transform Imaging Algorithm for General Airborne Bistatic High Squint SAR Data Focusing

作　　者：冉金和[1] 李修和[1] 

机构地区：[1]合肥电子工程学院,合肥230037

出　　处：《电子与信息学报》2014年第10期2469-2476,共8页Journal of Electronics & Information Technology

摘　　要：该文提出一般构型机载双站大斜视SAR的2维Chirp-Z变换(CZT)成像算法。针对双站大斜视回波信号的距离-方位向强耦合,在距离频域-方位时域校正载机大斜视引起的大距离走动,然后推导改进点目标的频谱公式。成像时,先用参考函数相乘完成回波一致聚焦,然后借助于载机轨迹解耦合公式将频谱相位分解为距离移变和方位移变的两个独立相位项,再运用CZT分别消除其空变性得到成像结果。仿真验证了该算法处理一般构型机载双站大斜视SAR回波数据的有效性。A two-dimensional Chirp-Z Transform （CZT） imaging algorithm for general bistatic high squint SAR is proposed. To deal with the serious range-azimuth cross coupling of echo signal in bistatic high squint SAR, Linear Range Walk Correction （LRWC） is performed in range frequency-azimuth time domain to correct the large LRW induced by the high squint model of platforms, and then the expression of a modified bistatic point target reference spectrum is derived. Reference Function Multiplication （RFM） is firstly performed to finish the bulk focusing. With the track decoupling formulas, phase terms of spectrum are decomposed into two independent phase terms as range-variant phase terms and azimuth-variant phase terms, and their space variances are eliminated by CZT respectively to get the focusing result. The simulation tests validate the effectiveness of the proposed imaging algorithm to focus the data of general airborne bistatic high squint SAR.

关 键 词：双站大斜视SAR 线性距离走动校正 Chirp—Z变换 成像算法 

分 类 号：TN958[电子电信—信号与信息处理]