NLOS mitigation in FMCW RADAR with CLEAN peak detection

摘要

A secondary frequency modulated continuous wave (FMCW) RADAR with two-way ranging can be used for indoor and outdoor positioning with high precision and accuracy. However, non-line-of-sight (NLOS) conditions lead to multipath effects that have a negative impact on the quality of ranging and positioning measurements, if the spectral analysis is not able to detect the correct line-of-sight (LOS) path. This work proposes an improved peak detection algorithm - based on CLEAN - that works on the base band spectra in each RADAR base station, in order to enable LOS path detection. In a simple ranging scenario at 3 m distance, the conventional parabolic interpolation for sub-bin resolution exhibits errors of up to 1.5 m (50%) for a large fraction of the measurements. The CLEAN algorithm, however, improves upon this by drastically reducing the number of outliers. In a positioning scenario, the parabolic interpolation exhibits errors between 0.2-0.8 m, the CLEAN algorithm reduces this error to below 0.5 m.