Interference Detection and Suppression Based on Time-Frequency Analysis

Radio frequency interference (RFI) is greatly harmful to Global Navigation Satellite System (GNSS) receivers.Sweep interference is one of the RFI for the GNSS receivers, which can degrade the performance of GNSS receivers seriously.In this paper, the Fractional Fourier Transform (FrFT) of time-frequency analysis is proposed in the GNSS interference detection and suppression.The FrFT method is tested for detecting and suppressing sweep interference, which is generated by a GNSS jammer.In the simulation experiment, the GNSS signal affected by sweep frequency interference is successfully captured after interference suppression by using the proposed method, which shows its effectiveness.The interference detection performance of the FrFT method is compared with the conventional techniques such as Short-Time Fourier transform (STFT) and Wigner-Ville distribution (WVD).The detection performance is improved by about a least one order of magnitude.In the aspect of interference suppression, a threshold method based on detection probability is proposed, and the performance of the proposed threshold method is compared with the conventional threshold methods.In the result, the interference tolerance is increased by 5 dB compared with the mean threshold method, and by 9 dB compared with the fixed threshold.