RFI Suppression Based on Time-Frequency Spectrogram for FMCW Radar

In this paper, an Radio Frequency Interference (RFI) suppression method using a spectrogram in the time-frequency domain for Frequency Modulated Continuous Wave (FMCW) radar is proposed. The proposed method has two main differences with previous methods published in the literature. First, the proposed method makes use of a time-frequency spectrogram, whereas a range-Doppler spectrogram is used in the literature. Thus, it is directly applicable to the range measurement of the radar as Doppler measurements are not always needed. Second, the proposed method makes use of a standard Fast Fourier Transform (FFT) of the received full-sweep Linear Frequency Modulation (LFM) signals, whereas Short-Time Fourier Transform (STFT) is mostly applied in the literature. Thus, it offers an efficiency advantage as STFT usually contains a large percentage of redundant / overlapping data and hence more resource consuming than FFT. Furthermore, this paper demonstrates a successful real-time implementation of the proposed method to resolve RFI problems in an FMCW coastal surveillance radar due to the presence of a neighboring high-power radar.