A new deramping algorithm for airborne squint-mode spotlight SAR data processing

This paper presents a new airborne squint-mode spotlight SAR data focusing algorithm based on a two-step processing strategy that combines the advantages of the efficiency of spectral analysis (SPECAN) algorithm and the precision of wavenumber domain (WD) algorithm. The first step of the proposed algorithm implements a modified SPECAN processing to the range compressed echo signal. This operation can eliminate azimuth spectrum folding effect and migrate and scale the azimuth data support. Then the residual and precision focusing of the SAR data is achieved by applying the WD algorithm requiring some modifications and implemented in the frequency domain. Finally, experiments carried out on simulated data confirm the validity of the presented approach.