Apparatus and method for detecting obstacles in the path of a moving vehicle

摘要

Obstacles in the path of a vehicle are detected by an ultrasonic radar system which measures the time between the instance of transmission of an ultrasonic wave pulse and another instance of reception of an echo signal. The transmitting period is controlled to be retarded from a reference or standard transmitting period by a time length including the measured time at every other transmitting period. The measured time is compared with a reference time to check whether a detected obstacle is within a dangerous range. This comparison is effected at every other transmitting period so that a false detection signal caused from a far obstacles is prevented from being produced. As a result of the comparison an alarming device is energized to alert the vehicle driver when necessary.