Effect of Antenna Offsets in Elevation on the Bi-Static Radar Scattering of Bicyclists

Automated and connected driving technologies enable a safer and more efficient road traffic, with radar sensors for environmental monitoring as one key element. Besides monostatic radar, bi-static radar sensing offers great potential for increasing the radar visibility of vulnerable road users. In this study, bi-static radar measurements of a bicyclist dummy conforming to the new car assessment programme were performed in the frequency range between 2 GHz and 18 GHz. A spherical measurement system was used to illuminate the target from different bi-static angles and different elevation angles, in order to study the differences in radar cross section (RCS). In view of different mounting positions of radar sensors, the emphasis was on the elevation angle. The RCS-values varied by up to 18 dB compared to the antennas mounted at the same height. The essential positions for bi-static radar scenarios resulted in variations of up to 7 dB. The results demonstrate the importance of considering the elevation angle and the need to extend current research to fully three-dimensional characterization.