HF Radio-Frequency Interference Mitigation

The dense radio-frequency interference (RFI) distributed on the spectrum in the high-frequency band greatly degrades the performance of radio systems and makes it urgent to find an effective and speedy method to eliminate the interferences. The interference mitigation method introduced in this letter is implemented before any further signal processing. It reconstructs the interference by the exactly estimated frequency, amplitude, and phase parameters in the signal spectrum and then subtracts the artificial interference from the input time-domain complex signal. The procedure steps of the method are illustrated in detail. The data stream of continuous oblique-incident ionospheric detection has been processed effectively and rapidly in real time. Several delay-Doppler ionograms severely contaminated by RFI are selected and presented. Comparisons of the original and mitigated ionograms and the signal-to-noise ratio (SNR) data show that the RFIs are eliminated perfectly and that the SNR is greatly improved.