Radar apparatus of automotive vehicle for producing accurate beam axis correction value

A radar apparatus of an automotive vehicle, which corrects a beam emission axis in accordance with a correction value to eliminate an error of the beam emission axis to a straight line path of the vehicle with respect to a horizontal direction, comprising:

• a radar unit outputting signals at intervals of a predetermined time, each signal indicating a scanned angle of a target as well as a relative distance of the target at an output time;
• a target detecting unit detecting the scanned angle and the relative distance of the target from each of the signals output by said radar unit when the target moves forward in a roadway lane different from a roadway lane of the vehicle or when the target is a fixed road-side object;
• and
• a correction value determining unit generating changes of the scanned angle and the relative distance of the target detected by said target detecting unit within a period from an initial output time to a final output time, and determining a correction value from said changes so that an error of the beam emission axis to the straight line path of the vehicle with respect to the horizontal direction is eliminated.