Radio frequency interference suppression based on two-dimensional frequency domain notch for P-band ultra-wideband SAR

Abstract

P-band ultra-wideband synthetic aperture radar (UWB SAR) not only has the characteristics of the high-resolution imaging, but also has the well capability of the foliage penetrating, which is potential of detecting and imaging the concealed target under the vegetation. However, there are a lot of the radio, television and mobile communication signals in the P-band, which are called as the radio frequency interference (RFI) signals. These RFI signals are mixed with target echo signals, which will cause the serious interference in the P-band UWB SAR imaging. The traditional notch method is easy to implement the RFI suppression, so it has been widely used. However, the traditional notch method is to notch each pulse echo individually, which has a high computational complexity. At the same time, the RFI suppression of each pulse echo separately will always lead to a large amount of the residual interference, so the traditional notch method has the poor RFI suppression effect. Based on the traditional notch method, this paper proposes an RFI suppression method based on the two-dimensional frequency domain (2DFD) notch, which can realize one-time processing of all echo pulses so that improve the efficiency of the RFI suppression. Meanwhile, because the bandwidth of the RFI signal is much smaller than that of the SAR echo signal, converting the received SAR echo signal to the 2DFD can further concentrate the energy of the RFI signals, so it has the better RFI suppression effect. The simulation results show that the proposed RFI suppression method based on the 2DFD notch can not only improve the efficiency of the RFI suppression but also have the better effect of the RFI suppression.