24 GHz and 77 GHz Radar Characteristics of Metal Guardrail for the Development of Metal Guardrail Surrogate for Road Departure Mitigation System Testing

Road departure mitigation system (RDMS) is a new vehicle active safety technology. Unlike Lane Departure Warning System (LDWS) and Lane Keeping Assistant System (LKAS), which relies on the lane marking to detect road edge, RDMS may not rely on the lane markings and can use the road edge and roadside objects to detect vehicle road departure. Since metal guardrail is a very common type of roadside boundary in the United States, RDMS may use metal guardrail as a reference to detect the road edge. Using real metal guardrails to test the performance of RDMS is difficult. One way to perform RDMS testing is to use a metal guardrail surrogate that has the similar properties to the real metal guardrail when sensed by the most common automotive sensors, such as radar, LIDAR, camera, etc., but will not damage the vehicle if being impacted. This paper describes the study of the 77GHz and 24GHz Radar Cross Section (RCS) of the real metal guardrail. The result will be used as the radar specifications for designing metal guardrail surrogate for the evaluation of RDMS.