星机双基地SAR空间几何关系与信号模型  

Study on Geometry and Signal Model of Spaceborne/Airborne Bi-static SAR

作　　者：周鹏[1,2] 皮亦鸣[1] 

机构地区：[1]电子科技大学,电子工程学院,四川成都610054 [2]中国石油大学(华东),信息与控制工程学院

出　　处：《遥感学报》2008年第5期750-758,共9页NATIONAL REMOTE SENSING BULLETIN

基　　金：国家自然科学基金资助项目(编号:60772143);教育部新世纪优秀人才支持计划资助项目(编号:23901019);四川省青年科技基金会资助项目(编号:06ZQ026-006)

摘　　要：星机双基地SAR是近年来在国外出现的一种新型空间对地观测传感器。由于卫星平台与飞机平台在飞行速度、飞行高度等方面存在巨大差异,其与较早开展的星载双基地SAR、机载双基地SAR等系统相比具有显著的不同。针对星机双基地SAR系统的3个基础性问题,同时也是非常关键的问题开展了研究工作。即:空间几何关系、多普勒特性和信号模型。从提高分辨率、利于直达波的接收和利于空间同步等角度出发,分析了飞机的适宜路线;推导了计算多普勒参数的精确解析公式;建立了系统的信号模型,分析了成像算法设计的难度;验证了在系统满足特定条件时,传统RD算法经适当改进后仍可适用。在此基础上,可进一步开展任意飞行模式下的成像算法设计等后继研究工作。In recent years,spaceborne/airborne bi-static synthetic aperture radar(SA-BSAR) has been proposed as a new kind of microwave remote sensor.The development of SA-BSAR is still at an early stage since there are many challenges faced ahead.Due to the huge difference between the satellites' and the aircrafts' velocities and flying altitudes,there are obvious differences between SA-BSAR and the earlier bi-static SAR systems which have symmetrical structures,such as the spaceborne bi-static SAR and the airborne bi-static SAR.Three basic and critical issues in SA-BSAR are discussed,including geometry,Doppler properties and signal model.In the discussion of geometry,the proper coordinate systems are first established to describe the movement of the satellite and the aircraft.Next,the appropriate flight path for the aircraft is quantitatively analyzed in detail from many aspects,including: how to improve the range resolution,how to improve the azimuth resolution,how to receive the direct path signal more conveniently,and how to make the spatial synchronization much easier.The following conclusions are drawn: the aircraft should fly on the same side of the imaging scene with the satellite;the difference angles among the platforms' course angles can not be too large;the aircraft must be illuminated by the satellite's main beam within the imaging time;the aircraft must appear at the right position just in time to cooperate with the satellite to implement the spatial synchronization.In the discussion of Doppler properties,several analytical formulae for computing Doppler parameters are first derived using the method of vector analysis.Afterwards,to make the formulae more practical,the derived expressions are transformed to an easy-to-use form that is expressed by orbit elements of the satellite,satellite antenna pointing angles and kinematical parameters of the aircraft.In the discussion of signal model,the model for SA-BSAR is first established based on the model for mono-static SAR and then the great difficulties in designi

关 键 词：星机双基地SAR 空间几何关系 多普勒参数 信号模型 

分 类 号：TN957.52[电子电信—信号与信息处理]