The Ultrasonic Sensor for Parking is a sensor dedicated to be used in low speed maneuvering situations (Speed < 10 km/hour). It measures the time of flight to an object (Echo-Localization principle).
The sensor sends an ultrasound echo (wave) and receives a signal (wave reflection by an object) after a certain period of time. The time of flight is converted to a measured distance. Software for the ultrasonic signal processing (designed by Continental) located in the ECU, interprets these measurements and determines the appropriate actions to take.