An object of the present invention is to provide a method capable of calibrating a sensor function required in a safety design of a radar safety sensor in real time.
A calibration station (11) is provided on a traveling route of an unmanned vehicle (1) on which a safety sensor (3) for detecting an obstacle (2) ahead is mounted, and a standard reflection is provided at a position of a maximum measurement distance (L) of the safety sensor (3) at the calibration station (11). Prior to normal traveling of the unmanned trolley 1, the unmanned trolley 1 is moved to the calibration station 11 in advance, and the reference value obtained by measuring the standard reflector 12 with the safety sensor 3 is taught, During normal operation of the unmanned trolley 1, every time the unmanned trolley 1 reaches the calibration station 11, the measured value obtained by measuring the standard reflector 12 by the safety sensor 3 is compared with a reference value. Calibrate the sensor function of FIG. 1.