Application of the frequency-domain synthetic bandwidth approach in Polar Format Algorithm

The problem of wide bandwidth management in current ultra-high resolution spotlight SAR systems could be solved by adopting stepped chirps and utilizing synthetic bandwidth approach. High resolution SAR image formation is a non-separable 2-D impulse compression processing, so the synthetic bandwidth procedure should be modified correspondingly with the image formation algorithm adopted. This paper demonstrates the application of frequency-domain synthetic bandwidth approach in SAR Polar Format Algorithm (PFA). The problem of motion compensation between the subpulses within a burst is discussed, and the signal processing flows are investigated in detail. The presented approach is validated by point target simulation.