How Car Parking Sensor Works With Park Assist: Check BMW 5 Series Saloon!!

Automatic parking aided by a cart parking sensor is increasingly becoming common day after day. Car parking, especially in busy designated parking areas, is a hectic exercise to not only the newly trained drivers but also the most experienced. Auto tech is taking the world by storm and the faster we learn and adopt every bit of it the better; how car parking sensor works is no exception.

With cars like Lexus LS 460, Lincoln Navigator, Cadillac CTS, Volvo S90 and the classy BMW 5 Series just to mention a few coming with park assist, car parking sensors are inevitable. The body size of these cars plus the shrinking parking spots have greatly catalyzed the increased use of parking sensors. Both front and reverse parking sensors are widely available in the market.


So, if you are interested in knowing how car parking sensor works, this is the best place for you.Before we delve deeper into the topic, it’s good to learn some basics.

What is Car Parking Sensor?

Car parking sensor is a feature that helps drivers detect obstacles behind and in front of the car and aids them to safely park their cars in those tight parking spots. These features, otherwise sensors use different working principles to detect and send alerts to the driver.

Parking sensors are available in many different brand names. But are there any designed for a specific car? Whether driving a Mercedes Benz or McLaren, any sensor if fitted correctly will theoretically function in any car model: fitted at the front or rear bumper.

Every self-parking car is synonymous with parking sensors. For a car to automatically detect open parking spots and steer itself off the road without hitting other cars is not magic. Park Assist an automatic parking aid in conjunction with car parking sensors are responsible.

Parking sensors come with a myriad of benefits. Drivers are less fatigued while parking their cars, no hitting other cars, less time to park the car and adding some confidence to the driver are some of the few benefits.
Now, how do car parking sensors relate to automatic parking?


Automatic parking is the use of sensors and cameras to typically scan for suitable space and once detected, the car automatically controls the steering as the driver controls the pedals. For the cars top start scanning for a parking space, the driver has to press the park assist button and then drive a certain low speed.
How Car Parking Sensor Works?

Firstly, car parking sensors use different principles to detect and convey messages or alert the driver.
There are two different types of sensors: Namely:
1.Ultrasonic Proximity Sensors
2.Electromagnetic Proximity Sensors

Both the Ultrasonic and Electromagnetic proximity sensors commonly use car parking sensors in their different working principles. Other than the additional cameras in the Electromagnetic system, sensors are the main components in the two entire systems.

Ultrasonic Parking Sensors

The beeping sound that keeps increasing as the car nears an object characterizes the Ultrasonic Proximity sensors. Ultrasonic sensors use a single transducer to send and receive the emitted and reflected ultrasonic sound waves and to calculate the proximity of the object.

Just like the famous flying nocturnal mammal-bat, that sends acoustic pulses which if reflected signals the presence of an object in front and then makes a split-second course change. This is the same principle used in Ultrasonic parking sensor system. The sensors connect to an alarm system that keeps beeping the faster the car draws nearer to the reflecting obstacle.

Ultrasonic sensors work by sending sound waves at a frequency above human hearing. A transducer, which is a component in the sensors acting as a microphone send and receives the ultrasonic sound in echo patterns. The sensors use the principle of time and speed to calculate the distance between the object reflecting the sound and the car. By taking the time lapses between sending and receiving the ultrasonic lapses and speed, the sensor can calculate the distance.


sensors formula

Using the formula Distance L = 1/2 × T × C, where T represents the time-lapse and is multiplied by ½ because it’s the distance to and from the transducer and C is the speed.

Ultrasonic sensors use high-frequency sound waves reflected from objects to send alerts to the driver. And this is the main setback for these parking sensors. Parking in underground tunnels and when raining is a great challenge.

Electromagnetic Proximity sensors

Electromagnetic Proximity sensors use electromagnetic sensors to detect obstacles within the range through electromagnetic frequencies. These types of sensors are best for detecting a wide range of wavelengths within the electromagnetic spectrum. The whole system uses radar technology to send out radio waves.

Once the radio wave is reflected, the returning wave bears a different characteristic compared to the emitted waves. The ECU receives information from the radio receiver and then calculates the speed and distance.
Electromagnetic parking sensors creates an electromagnetic field around the car. Any object that comes within this field is detected and a signal send to the driver’s dashboard.

This Electromagnetic parking system nowadays commonly features cameras the displays a vie rear when engaged in the reverse gear. The video further aids the driver when reversing thus making it a fun-filled exercise. One of the advantages of using this system is it detects a wider range of objects compared to the Ultrasonic Parking system.
Both front and reverse parking sensors use the same principles as per the installed system to detect and send signals to the dashboard or through a beeping sound.



Every car-parking sensor employs a certain theory in its working principle. This certainly means every specific sensor works differently from each other. However, all car-parking sensors fall under two categories: the Ultrasonic Proximity sensor and Electromagnetic Proximity sensor.

How car parking sensor works especially if the car has the Park Assist system is also determined type of sensors mounted in the car. And even though these parking sensors have different brand names for commercial purposes, their working principle lies within the two categories explained above.

If you want to know which automotive are equipped with automatic parking sensor, and want to read more articles about cars, WapCar is very great place to visit.

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