IMAR Results

Optimized Interference Mitigation Method for Automotive Radars

A computationally efficient method for the mitigation of uncorrelated automotive radar interferences was developed during the first year of the project. The idea of the method is to compute the STFT of the beat signal and sort each constant frequency line of the spectrogram in ascending order (L-statistics), which places the bins affected by interference towards the right-hand side of the time-frequency plane. Onwards, the interference-free range profile is computed by a coherent summation along the time axis of the bins considered to be unaffected by interference (the first q% of time bins from the sorted spectrogram). The impact of the STFT parameters (sliding window length and step size) and the summation percentage q on the method’s performances and computation time was investigated using a synthetic dataset that contains 24000 samples of realistic automotive radar signals (with multiple targets and interference sources). Moreover, it was shown that by increasing the sliding window step size to half the window’s length the computation time decreases significantly and we obtain similar performances to the case with unitary step size (the original approach used as starting point for this project), which makes the method more suitable for real-time implementation on a digital signal processor. 

Visual illustration of the interference mitigation method: Examples of the spectrograms (left) and ordered spectrograms (right) of a beat signal with a variable number of interference sources: 1 (a,b), 2 (c,d), 3 (e,f). After the spectrogram is sorted, the target signals are clearly separated from the interference patterns and the range profile can be accurately recovered by a coherent summation over part of the time bins [1].