Driver assistance systems.

It is often necessary to manoeuvre you car into tight parking spaces, especially in towns and cities. The Volkswagen parking sensor systems help the driver to manoeuvre into tight spaces and reduce stress by informing the driver of the distance from obstacles by means of acoustic or, depending on model, optical signals.

The most important elements of the parking sensor systems are the ultrasonic sensors, with up to six of these located each in the rear and/or front bumpers. Thanks to the combination of sensors and electronics, the ultrasonic sensors are noted for their compact design. Due to this and the fact that they are painted in the body colour, they are barely visible. The sensors monitor a range of up to 150 centimetres behind and, depending on the Volkswagen model, in front of the vehicle. The system is activated when reverse gear is engaged or below a speed of 15 km/h.

The system uses the principle of the echo sounder. The control unit periodically triggers the sensors which emit an ultrasonic signal with a frequency of 40 kHz (kilohertz). The control unit then switches the sensors to reception, so that they can pick up the sound waves reflected off the object. Based on the passage time of the ultrasonic waves, in other words the time that elapses between emitting the signal and receiving the reflection, the system calculates how far the sensor is from the obstacle. The control unit calculates the distance between the vehicle and the obstacle based on the information from at least two sensors using the triangulation method.