Comparison of real-time time-frequency RFI mitigation techniques in microwave radiometry

Radio-Frequency Interference (RFI) is a well-known problem for Microwave Radiometers (MWR). A number of RFI mitigation techniques have been studied to deal with RFI from the receiver's side. In this study, a comparison in terms of performance among several real-time time-frequency RFI mitigation techniques is presented. Time-frequency techniques are of high importance because the vast majority of RFI signals are well-localized in the time-frequency space. The five techniques compared under study are: Pulse Blanking (PB), Frequency Blanking (FB), Spectrogram Blanking (SB), Wavelet Denoising (WD), and Multiresolution Fourier Transform (MFT). Results show that the best performance depends on the particular type of RFI, and occurs when the transform basis is similar to the RFI, that is, the projection on that particular basis is maximized. However, there is not a single technique that is effective for all RFI signals, and future approaches may be based on a combination of several techniques.