The research on notch filtering and spectral filling for RFI suppression

Radio frequency interference (RFI) suppression has become an essential step in synthetic aperture radar (SAR) imaging processing. In this paper, a spectral filling filtering method for RFI suppression referred to notch filter is derived and analysed. The derivation results show the reason for the “residual terms” after suppression processing in frequency domain and the influence of the “residual terms”. And a conclusion is drawn: the essence of interference suppression based on spectral filling filter is the dynamic change process of “residual terms”. Since they cannot be completely eliminated in theory, they will affect the image quality after interference suppression, but the effect of spectral filling method is better than that of the notch filter method. The conclusion is verified by the simulation experiment.