FRFT-Based Interference Suppression for Automotive FMCW Radars

Automotive radars are widely deployed in advanced driver assistance systems (ADASs) and autonomous driving. However, the increased vehicles equipped with radars make mutual interferences in automotive radars become an nonnegligible issue. The incoherent interferences between automotive frequency modulated continuous wave (FMCW) radars can significantly increase the noise level, leading to the degeneration of target detection. To address the problem, this article proposes an interference suppression approach based on the Fractional Fourier Transform (FRFT). It is noted that the interference component in the intermediate frequency (IF) signal exhibits chirp-like characteristics, which shows the energy concentration in a FRFT domain. Therefore, the interference component can be easily filtered out in the FRFT domain. Additionally, to decrease the computational cost in the presence of multiple interferences, a two-dimensional (2-D) constant false alarm rate (CFAR) detector is utilized to detect interference components. The proposed approach is also effective in scenarios with a large proportion of interference samples. Both simulations and field experiments demonstrate the performance of the proposed approach.