基于CZT的机载并行双站斜视SAR成像算法  

Airborne Bistatic SAR Imaging Algorithm for Parallel Squint Mode Based on CZT

作　　者：武拥军[1,2] 吴先良[1] 

机构地区：[1]安徽大学计算智能与信号处理教育部重点实验室,安徽合肥230039 [2]合肥电子工程学院信息系,安徽合肥230037

出　　处：《航空学报》2010年第4期825-830,共6页Acta Aeronautica et Astronautica Sinica

基　　金：国家自然科学基金(60671051);高等学校博士学科点专项科研基金(20060357004)

摘　　要：建立了机载并行双站斜视合成孔径雷达(SAR)的几何模型,给出了雷达回波的数学表达式,推导了它的二维频谱并对其特点做了分析。在二维频域内,先用聚焦函数对观测场景中心的点目标做精确成像,然后用Chirp-Z变换(CZT)校正中心点两侧目标回波的距离徙动,再通过方位向逆傅里叶变换得到了雷达图像。该算法利用了CZT能够处理非线性调频信号的特点,简化了处理过程,提高了计算效率和成像精度。仿真实验验证了这种基于CZT的新算法在处理并行双站斜视SAR数据时的有效性。This article establishes the geometric model of an airborne bistatic synthetic aperture radar （SAR） for the parallel squint mode and presents the expression of the radar echoes,and then derives its two-dimensional spectrum with an analysis of its characteristics. In the two-dimensional frequency domain,the point targets in the center of the observed scene are precisely imaged by multiplying the focusing function,and then the Chirp-Z transforms （CZTs） are employed to correct the range cell migration of the target echoes in either side of the center points. Finally,radar images are generated by the inverse Fourier transform on the azimuth direction. Since the algorithm utilizes the property of the CZT to process the nonlinear modulation frequency signals,the processing procedure is simplified,and computational efficiency and imaging precision are greatly improved. The simulation tests validate this new algorithm based on the CZT to process the data of the airborne bistatic SAR for the parallel squint mode.

关 键 词：合成孔径雷达 二维频谱 聚焦函数 CHIRP-Z变换 成像算法 

分 类 号：V243[航空宇航科学与技术—飞行器设计] TN757.73[电子电信—电路与系统]