How do Parking Sensors Work?

Parking sensor is an active driver assistance system when parking. Ultrasonic sensors play the main role in it. Parktronic appeared in the early 90s and was originally set on premium cars.

In an urban environment, such a system is very helpful for drivers. You may simply not see a trash can, a high curb or a left cart when parking. Parktronic sees these obstacles and warns the driver about them in a timely manner. The parking radar system may include: sensors; control unit (receives and analyzes the signal); speaker (beeps); display or indicator (set in the cabin and shows the distance to the obstacle).

How do parking sensors work?

The sensors are usually installed on the rear bumper. But now more often they can be found in the front. Ultrasonic sensors detect obstacles within a radius of 0.2 to 2 meters. If there is any obstacle, a sound signal is emitted or data is displayed on the display.

The work of ultrasonic sensors can be compared to an echo sounder. The supplied signal is reflected from the obstacle and returned back. The system analyzes the wavelength and determines the distance to the object. All this happens very quickly. Depending on the equipment, the system can alert the driver in different ways. The simplest way is to give a pulsating signal. The closer the obstacle, the stronger and louder the signal will be. It becomes continuous with the closest approach.

More advanced models use a visual indicator or display in the show room. The distance is displayed in the form of divisions, numbers or images on the screen. Parking sensors work together with a rear view camera in the most expensive modifications. The screen displays the car image, its trajectory, speed and objects around.

Number of sensors

Systems can vary in the number of sensors and their location. The more they have, the more correct the information will be. In parktronic systems, there can be from 2 to 8 pieces. In the most budgetary options, only two sensors are set. The cost of this configuration is much lower. But two sensors cannot cover the whole space and see some low or thin objects. They have their own “dead zone”.

The most common option is the four-sensor system on the rear bumper. This quantity is optimal in terms of cost and quality of detection. The system will not react to cars driving behind. Rear parking sensors are activated when stopping and engaging reverse gear. In systems with six sensors, four are placed at the back and two at the front. The front sensors also help detect foreign objects. Eight sensors have the most expensive and advanced models. They scan the space on both car sides. In order not to bother the driver with a constant squeak, the system switches on only after pressing the brake. So the radar understands that now there will be a backward maneuver. After 20 seconds, the system shuts down by itself. The front parking sensors usually work independently of the rear ones and are controlled by a speed sensor. At speeds less than 20 km / h, the front parking sensors are disabled.

Types of parking sensors

Ultrasonic

The most common parking radar system, the principle of which was described above. Works by scanning space with ultrasonic waves.

Electromagnetic parking sensors (tape)

This kind of parking sensors creates an electromagnetic field that also acts as a radar. It is a metallized tape. It attaches to the back of the bumper or trunk. It is unvisible from the outside. There is no need to drill holes in the bumper. Electromagnetic parking sensors can detect an object at a distance of 5 cm, and ultrasonic – from 20 cm. Also, dirt does not interfere with it.

But electromagnetic radar can be affected by other sources of electromagnetic radiation. This can happen quite often in the city. Also, you cannot reduce or increase the sensitivity of such a radar.

Ultrasonic sensors can determine the size and location of an obstacle, but an electromagnetic one cannot do this, since it is alone.

Wireless parking sensors

Wireless sensors send a radio signal to the control unit. It is a more modern system that is becoming more and more popular. The technology is convenient because there is no need to lay wires from each sensor.