一种新的星机双基地SAR空间同步方法

A New Approach for Spatial Synchronization in Spaceborne/Airborne Hybrid Bi-static SAR

由于卫星与飞机在飞行速度上的巨大差异,收发平台波束足迹的空间同步是星机双基地合成孔径雷达(Spaceborne/Airborne Hybrid Bistatic Synthetic Aperture Radar,SA-BSAR)的一大技术难点。已经有学者提出了一种基于波束指向控制的同步方法,但该方法存在着成像时间短、算法复杂、方位分辨率低等缺点。提出了一种基于宽波束照射的新方法,对新方法的可行性进行了充分的量化论证和仿真验证。与已有方法相比,所能获得的场景长度略小,但成像时间更长,方位分辨率更高。最后,分析了两种方法的优缺点,明确了各自的适用场合。

The spatial synchronization of the antenna footprints is a big methodical and technological challenge in spaceborne/airborne hybrid bi-static SAR（SA-BSAR） ,due to the fact that there is great difference between the velocities of the platforms. A method by performing beam steering on both sides has been given in the published literature. However,there are some disadvantages in that approach such as short imaging time,requiring complex processing and low azimuth resolution. To overcome these disadvantages,a new approach based on wide-beam illumination is proposed. The feasibility of the new approach is demonstrated by both numerical analysis and simulation results. Several performance parameters for the two methods are quantitatively compared. When the new approach is applied, the scene extension is slightly shorter while the imaging time is much longer and the azimuth resolution is higher. Advantages and disadvantages of each approach and their respective scopes of application are analyzed.