Vertical digital beamforming versus vertical Doppler Beam Sharpening

This contribution presents a comparison of the Vertical Digital Beamforming (DBF) approach with the Doppler Beam Sharpening (DBS) method for target height finding. The purpose of the comparison is to determine which of the two approaches more accurately estimates height using a Frequency Modulation Continuous Wave (FMCW) automotive radar. First the process of peak detection and target number extraction is described, then the three dimensional (3D) high resolution recursive Fourier algorithm RELAX is used to enhance the range, Doppler, and angular resolution of the detected targets. Next, the DBF and the DBS algorithms are described, and used to estimate the height of an entrance gate 4.5 m high, based on the RELAX output spectrum. Finally height measurement results of DBF and DBS are shown, discussed and compared. The results show that DBS is a powerful and hardware efficient method capable of retrieving very accurate target heights, without requiring multiple vertical antennas.