Abstract: A system for avoiding obstacles in the path of a vehicle including a sensor assembly having a field of view with a plurality of sectors for detecting the distance of objects within each sector. The system further includes an element for identifying obstructed sensors in which objects are detected within a predetermined range and a device for selecting an unobstructed sector close in alignment to the direction of the path to designate around the object a clear path which is close to the original path.

Abstract: An ultrasonic ranging system includes transformer means with a transformer which is selectively energized to produce a transducer drive signal. An ultrasonic transducer transmits an ultrasonic pulse in response to the drive signal and develops an echo signal upon receipt of an echo pulse derived from the ultrasonic pulse; a shunt switch is connected across a winding of the transformer and is selectively closed to quickly damp the ringing following the transmission of an ultrasonic pulse to a level substantially below the level of the echo signal to permit close ranging.