Automotive radar has been described as one of the most significant additions to vehicles in the past two decades. In a 3D form, measuring azimuth (horizontal angle) distance and velocity, radar is used in cruise control and automatic emergency braking systems in advanced driver assistance systems (ADAS). As Safety Level 3 vehicles enter the market, radar has progressed to 4D, measuring elevation direction to detect how high an object is from the ground to determine if it is a kerbstone or a pedestrian.