Automotive Radar Multipath Propagation in Uncertain Environments

Future use of high-resolution near range radar sensors for vehicle environment perception is facing challenges in terms of detection and correct assignment of multipath reflections (false-positives) from surfaces and obstacles. This paper presents a novel geometric model to determine the relative positions from surrounding targets and reflection surfaces assuming that every object moves on a circular path to a mutual center. Principles of electromagnetic wave propagation under consideration of incident wave angles at potential reflection surfaces are described. Radar measurements illuminating an experimental target and a highway barrier as reflection surface, which reproducibly generates several multipath reflections, were carried out in a deterministic test environment and validate our presented methods. The installation of absorption material at intense reflection areas was conducted as countermeasure to reduce the intensity of false-positive detections. Furthermore, a realistic urban driving scenario using a real vehicle as target object and a building wall was reconstructed to proof field relevance.