Radar-interference-based bridge identification for collision avoidance systems

Automotive radar sensors are commonly used for providing environment information required by driver assistance systems. Although they show a good performance in measuring the distance and the speed of other objects even under poor weather conditions, they suffer from the shortcoming of a missing resolution in elevation. Consequently bridges crossing the lane of the ego vehicle may look similar to stationary obstacles. This contribution shows a bridge identification algorithm based on the interference pattern resulting from the multipath propagation of the radar wave. During the approaching to bridges or stationary obstacles, the pattern leads to a variation in the backscattered power from the object. This variation can be used to make statements about the object height position above the road. Results calculated from real scanning radar sensor data show the usability in real traffic scenarios.