PDC sensor reversing radar
A PDC sensor reversing radar is an ultrasonic-based detection system that helps drivers identify obstacles behind the vehicle during reversing. It emits ultrasonic signals and analyzes returning echoes to calculate distances, providing audible warnings to prevent collisions. This article covers the working principle, components, operation, and maintenance of reversing radar systems.
A PDC sensor reversing radar, commonly referred to as a reverse radar or parking radar, is an ultrasonic-based detection system installed in vehicles to assist drivers during reversing maneuvers. When reversing, the reversing radar emits ultrasonic signals through an ultrasonic sensor. The working principle of the reverse radar is based on ultrasonic ranging technology. The sensor is controlled by a microcomputer to emit ultrasonic signals, and when the signal encounters an obstacle and reflects back, the sensor receives the reflected signal. The system calculates the distance by determining the time elapsed between the transmission and reception of the ultrasonic signal. PDC systems are typically installed in the rear bumper or both front and rear bumpers with radar detectors to detect obstacles in front and behind the vehicle.
PDC Sensor
The reversing radar system consists of an ultrasonic sensor (commonly known as a probe), a controller, and a display or buzzer. The ultrasonic sensor uses the piezoelectric principle, utilizing the piezoelectric and inverse piezoelectric effects of piezoelectric ceramics to receive and transmit ultrasonic signals, thereby calculating the distance between the sensor and the detected target through the transmission time of the ultrasonic signal. The PDC system uses ultrasonic sensors to detect the distance to the nearest obstacle and emits a warning sound to alert the driver. The advantage of PDC is that the driver can use hearing to know the distance to obstacles or other vehicles when parking, and when the vehicle exceeds a certain speed, the system will automatically shut off. The PDC ECU controls the operating mode of each sensor by output of a digital signal on the signal line, with each sensor having two modes of operation: combined transmitter and receiver mode or receiver mode only.
The digital no-blind spot PDC reversing radar operates by automatically activating when reverse gear is engaged. Four ultrasonic sensors are embedded in the rear bumper of the car, and they start detecting obstacles behind the vehicle. The working principle of the reverse radar is based on ultrasonic ranging technology, where the sensor is controlled by a microcomputer to emit ultrasonic signals. When the signal encounters an obstacle and reflects back, the sensor receives the reflected signal. The system uses the ultrasonic signal from transmission to reception of the echo signal to calculate the distance based on the propagation speed in the medium, which allows the calculation of the distance between the probe and the detected object. The detection cycle consists of the ECU operating one sensor in the combined transmitter and receiver mode and transmitting a number of ultrasonic pulses, then switching the transmitting sensor and the adjacent sensor(s) to receiver mode. This sequence is repeated using a different sensor and continues until all sensors have output an ultrasonic signal, completing in approximately 100 ms.
The reversing radar provides audible warnings to alert the driver to obstacles. When an object is detected within the sensor's range, the system emits a pulse tone which increases in frequency as the vehicle gets closer to the object. PDC provides an audible warning to the driver when any obstacles are in the path of the vehicle during a reversing maneuver. The system helps the driver see invisible things in the rearview mirror and informs the driver of the obstacles around the vehicle. The maximum detection range varies by sensor position, with corner sensors typically having a range of approximately 600 mm (2 feet) and center sensors having a range of approximately 1500 mm (5 feet). The warning tone becomes continuous when the distance between the sensor and the obstruction is less than approximately 300 mm (1 foot). PDC will remain active until the vehicle speed exceeds approximately 32 km/h (20 mph) or until the vehicle has traveled approximately 50 meters (165 feet), when it will automatically deactivate.
Maintenance and proper use of the reversing radar system are important for reliable operation. Keep the sensors free from dirt, ice, and snow, as deposits building up on the surface of the sensors can impair their performance. When washing the vehicle, avoid aiming high pressure jets directly at the sensors at close range. The sensors may not be able to detect certain types of obstructions such as narrow posts, small objects close to the ground, and some objects with dark, non-reflective surfaces. The system is also subject to the physical limits that apply to all forms of ultrasonic measurement, and there is a blind spot in which objects cannot be detected. If a long, high pitched tone sounds and the switch indicator light flashes when PDC is activated, then a fault in the system has been detected. Regular diagnostic checks using appropriate tools can help identify and resolve issues before they affect system performance, ensuring the reversing radar continues to provide reliable assistance for all reversing maneuvers.
