A Novel Radio Frequency Interference Suppression Method for SAR Based on Spectrum Extrapolation

Radio frequency interference (RFI) is the most common interference of noise source that directly affects performance of wideband radar systems, especially for synthetic aperture radar (SAR). In this paper, a novel RFI mitigation approach for both narrow-band interference (NBI) and wide-band interference (WBI) is proposed. A rather simple but common technique for RFI filtering is to transform the data to the range-frequency domain and to cancel out frequency contributions in every range spectrum with amplitudes higher than a certain threshold. After RFI filtering, the resulting SAR image is with a coarser range resolution due to missed parts of the range frequency spectrum. A frequency domain Autoregressive (AR) model based on the spectrum extrapolation is introduced. Afterwards, the missed range frequency spectrum parts are recovered through spectrum extrapolation to improve the impaired range resolution. Simulation results validate the proposed approach.