What Principle Does the Reversing Radar Utilize?

[SanCorbin]

The principle of the reversing radar system involves the use of ultrasonic signals. Controlled by the microcomputer within the reversing radar host, the signals are emitted and received by the probes. By comparing the signal return time, the system calculates the distance to obstacles and then issues different alarm sounds via the alarm device. Below is a detailed introduction to the reversing radar system: 1. The reversing radar system consists of the reversing radar ECU, the reversing radar buzzer, and several (usually four) reversing radar sensors installed on the (rear) bumper. If a rear camera is installed, it provides an image of the rear area of the vehicle on the navigation screen. 2. When the vehicle is shifted into reverse gear, the reversing radar ECU monitors the area around the rear bumper using ultrasonic sensors. If an object is detected within the monitored area, the audible alarm device in the instrument cluster will sound a warning. The system can detect relatively hard solid obstacles as well as objects like wire mesh and fences. 3. The detection range of the two side sensors covers an area 60cm from the corners of the bumper. When the detected distance is less than 20cm on the sides or less than 30cm directly behind the center, the sound signal will become continuous to prevent a collision with the bumper.

[CalvinFitz]

I understand the principle of reverse parking sensors is based on ultrasonic technology, similar to bat echolocation. Sensors mounted on the rear of the vehicle emit high-frequency sound waves, which reflect back upon hitting an obstacle. The receiver captures the echo and calculates the time difference between emission and reception. Since the speed of sound in air is approximately 340 meters per second, the formula is distance equals speed multiplied by time divided by two. When the distance is short, the beeping sound inside the car speeds up and becomes more frequent, alerting you to stop. This design is quite ingenious, especially at night or in blind spots, preventing bumper scratches. Common issues include mud or rainwater interfering with the echo, causing false alarms. Remember to clean them regularly to ensure accuracy. Nowadays, some cars have upgraded to radar or cameras, but basic ultrasonic sensors remain mainstream—safe and economical.

[VonNoah]

I find the working principle of parking sensors quite intuitive, based on ultrasonic ranging. The transmitter sends out sound waves, which bounce back upon hitting an object. The system calculates the time difference between emission and reception, then multiplies it by the speed of sound to determine the distance. In practical use, the audible warning becomes more urgent as the distance decreases, greatly assisting with parking safety. When I had a narrow parking space, it helped me avoid hitting poles or low bushes. Although the principle is simple, its core function is preventing blind spot accidents, especially in urban alleys. In poor weather conditions like heavy rain, echo accuracy might decrease, so driving slower is advisable. Generally reliable, it's now standard equipment on new cars - affordable and practical. The technology evolved from marine sonar, with minor improvements like sensitivity adjustments after being adapted for automotive use.

[LaLeilani]

I see that the principle of the parking sensor is ultrasonic echo positioning. The sensor emits sound waves, which reflect back when encountering obstacles, and the time difference is calculated to determine the distance. The system uses this calculation to trigger an alarm sound, with the frequency speeding up as you get closer to assist in reversing. The design focuses on collision prevention, being practical and easy to maintain. Dirt needs to be wiped off to maintain accuracy.