Spectrum analysis of SAR image in polar grid system for back projection algorithm

In this paper, the analytic expression of synthetic aperture radar (SAR) image spectrum in the polar grid system is derived based on the wavenumber analysis. By revealing the relationship between wavenumber variable and image spectrum in the polar system, we can better understand the mechanism of fast factorized BP (FFBP) processing. Moreover, the form of phase error in spectral domain can be possibly revealed which will facilitate motion compensation and autofocusing in FFBP processing. Simulation results are presented and analyzed to demonstrate the validity of the derived spectrum.