Spotlight-mode SAR data focusing using a modified wavenumber domain algorithm

In this paper, a modified version of the wavenumber domain algorithm (MWDA) is analytically presented and formulated. It is capable of processing the spotlight-mode SAR data. MWDA combines the high accurate focusing of the wavenumber domain algorithm (which is also called range migration algorithm) and the interpolation-free requirement. To avoid costly interpolation manipulation, the inverse scaled Fourier transform (ISFT) is substituted for Stolt mapping. The subaperture processing is used to circumvent the limitation that the pulse repetition frequency (PRF) is not high enough to sample the signal in azimuth.