On the Mosaic mode spaceborne SAR

A new operating mode of synthetic aperture radar (SAR), referred to as Mosaic mode, can simultaneously obtain high azimuth resolution and wide swath. In Mosaic mode, the radar beam scans in the range direction while the strip line is advanced by steering antenna beam in the azimuth direction. The imaging bursts constituting Mosaic mode have the same acquisition geometry with squint spotlight mode. When the steering angle is large, the effect of the skew of two-dimensional (2-D) spectrum cannot be neglected. In this paper, a modified two-step approach is proposed to focus the data of Mosaic mode. It can remove the azimuth spectrum folding effect caused by the skew of the 2-D spectrum. Simulation results confirm the validity of the proposed algorithm.