Method to suppress radio-frequency interference in HF radars

The output of radio-frequency interference (RFI) after mixture with the local oscillator (LO) and lowpass filter is analysed, and some conclusions are drawn. Based on the conclusions, a new method is presented to suppress the RFI. The method performed well on ocean echo data acquired with the HF system OSMAR2000, and the detection distance has been increased by 25 km.