近空间被动双站SAR的成像性能分析

Imaging performance analysis for near-space passive bistatic SAR remote sensing

近年来,近空间受到了越来越广泛的关注。近空间飞行器兼具卫星和航空飞机的优点,能提供类似卫星的宽覆盖、长续航能力和飞机的快速响应能力,这为研究新体制遥感技术创造了条件。基于此,文章提出了一种基于近空间平台的被动双站合成孔径雷达(SAR)成像方法。首先,通过分析近空间被动双站SAR的空间几何模型,建立了其相应的SAR回波信号模型;然后,根据发射机和接收机对成像目标产生的多普勒效应,对近空间被动双站SAR成像的距离分辨率和方位分辨率进行了分析和仿真,并分析了近空间被动双站SAR存在的方位向调频率空变特性。最后,以接收机静止模式为例,对其成像处理进行了仿真。理论分析和仿真实验结果表明,近空间被动双站SAR是一种具有良好应用前景的遥感新技术。

The interest in near-space has increased greatly in recent years. As near-space has the combined advantages of airspace and aerospace, the sensors placed in near-space platforms can provide both wide coverage like spaeeborne sensors and fast revisit speed like airborne sensors. This opens a door to many new remote sensing applications. As such, this paper proposed a near-space aerocraftbased passive bistatic synthetic aperture radar （SAR） imaging technique. The spatial configuration and its corresponding signal model are described, along with the analysis of spatial resolutions including range resolution and azimuth resolution. The spatial variable characteristics of azimuth chirp rate and their impacts on subsequent high-resolution image formation are also investigated. Taking the passive receiver is stationary as an example, imaging simulations arc performed. Theoretical analysis and computer simulation results show that near-space passive bistatic SAR is indeed one promising remote sensing technique.