Processing of Airborne Video SAR Data Using the Modified Back Projection Algorithm

This article proposes an algorithm framework recently developed for video synthetic aperture radar (ViSAR) and presents the processing results of the airborne data collected by a W-band radar. This framework aims to accelerate the time-domain algorithm and produce synthetic aperture radar (SAR) video that has no change of view angle, which is highly desired in target tracking. The presented framework includes a few modified processing algorithms, where the strategy of subaperture recursion is proposed. The modified acceleration algorithm is used to avoid the interpolation and adapt to high squint angles without rotation of image grids. In addition, the conventional autofocus method has been improved to deal with urban data that usually contain strong scatterers. The algorithm framework can achieve SAR video without rotation of view angle with a lower computational load compared to other existing time-domain methods, which has been verified on airborne real data. Its processing efficiency becomes impressive if the apertures are highly overlapped in some cases that require a very high frame rate.