基于GPS的双基地SAR大斜视角成像算法研究  

Imaging Algorithm Research of Bistatic SAR Based on GPS under Large Squint Angle

作　　者：菅春晓[1] 

机构地区：[1]国防科学技术大学电子科学与工程学院,湖南长沙410073

出　　处：《现代电子技术》2009年第3期54-58,共5页Modern Electronics Technique

摘　　要：建立了基于GPS的顺轨SAR系统模型,通过将GPS信号等效为Chirp信号,研究了在该模式下的大斜视角Chirp Scaling算法。在正侧视或小斜视情况下,CS算法具有较好的聚焦性能和广泛的适用性,但在斜视角较大的情况下,该算法将散焦而不能成像,因而提出了用等效的单基地距离模型来代替双基地距离历史的方法,解决了大斜视角情况下距离模型二阶近似误差较大的问题,并结合单基地非线性CS算法,实现了在大斜视角情况下的基于GPS反射信号的双基地SAR高精度成像,最后通过Matlab仿真进行了验证。A system of along - track mode SAR based on the GPS is established. By seeing the GPS signal as a chirp,Chirp Scaling algorithm of this mode with large squint angle is investigated. Chirp scaling algorithm is considered more efficient and widely applicable when the bistatic SAR system is in side- look or small squint angle mode, but in large squint angle case,the errors caused by Taylor expansion are so large that the algorithm could lose its precision. In such a case,an equivalent monostatic SAR range mode which has fewer errors than Taylor expansion with large squint angle is proposed to substitute the range history of bistatic SAR. Then bistatic SAR images with large squint angles are gotten by common Nonlinear CS algorithm. The effectivity of the method is verified by Matlab simulation.

关 键 词：GPS 双基地合成孔径雷达 顺轨模式 大斜视角 非线性CS算法 

分 类 号：TN95[电子电信—信号与信息处理]