A modified notch filter for suppressing radio-frequency-interference in P-band SAR data

Faced with an increasingly complex electromagnetic environment of space, Synthetic Aperture Radar (SAR) is susceptible to the influence of the Radio Frequency Interference (RFI) signals, thus seriously affecting the SAR image interpretation. This is even worse for the low-frequency-band SAR systems (P-band for example) which are disturbed by a lot of television broadcasting signals. Based on the model and characteristics of the RFI signals, a modified RFI suppression method is proposed. This method combines the advantages of traditional notch method and subspace projection method in SAR RF interference suppression. This not only reduces the false-alarm probability that introduced by the subspace projection method during the interference suppression process, but also provides a more accurate determination threshold and a better weight for notching, which can effectively enhance the interference suppression effect. The simulation results show that the proposed method is better than the subspace projecting method and the notch method.