As a crucial device in the field of automotive safety, reverse parking sensors—often referred to as an "invisible measuring tool"—have played a key role in ensuring vehicle safety during reversing since their inception. Through professional technical means, Beijing Allinby has successfully unveiled the mysteries of the ultrasonic technology behind these sensors, providing robust data support for the development of the industry.

A complete reverse parking sensor system consists of three components: ultrasonic sensors, a controller, and a display. The ultrasonic sensors are responsible for transmitting and receiving ultrasonic signals; the controller processes these signals to accurately calculate the distance and position of obstacles; the display intuitively presents this information to the driver, and triggers an audio-visual alarm when the distance to an obstacle reaches a dangerous threshold. Its working process involves three key steps:

First, the controller instructs the ultrasonic sensors to emit ultrasonic waves, while simultaneously receiving the reflected waves.

Next, by calculating the time difference between the emission and return of the ultrasonic waves, and combining it with the known speed of sound (340 m/s), the distance to the obstacle is determined.

Finally, the display feeds back the result to the driver to provide safety prompts.

Ultrasonic waves are invisible, intangible, and inaudible to the human ear. To visually demonstrate these signals, engineers at Allinby built a professional measurement system: they used a Q041H-T-2 data acquisition instrument (supporting a 192 kHz sampling rate) paired with an MNP4120 microphone (with a frequency range of 4–100 kHz) to conduct tests on the reverse parking sensors of a brand's SUV and sedan.

Test results showed that the ultrasonic ranging signals of both vehicle models were fast, transient, and strong, with a main frequency of approximately 51 kHz and high energy. Randomly sampled signals all consisted of 16 cycles of ultrasonic waves at around 51 kHz, showing no significant differences between the two models. However, the sedan emitted 12 signals within 2 seconds, while the SUV emitted 18 signals. This study visualized the invisible ultrasonic signals, laying a solid data foundation for in-depth exploration of reverse parking sensor technology.

Based on the outcomes of this test, Beijing Allinby, leveraging its independent R&D capabilities, successfully launched an automotive reverse parking sensor acoustic testing system. The system features a clear and efficient testing process, comprising three core steps:

First, the system enables radar wave emission and synchronous signal reception.

Next, it performs automatic waveform extraction and peak frequency calculation.

Finally, it completes frequency and sound pressure level detection, as well as power adjustment—comprehensively ensuring the integrity and scientific validity of the test.

Additionally, this system boasts several notable advantages:

• Fully automated process

• High extraction accuracy

• Data traceability

• User-friendly operation

• Strong expandability

With the accelerated advancement of automotive intelligence and connectivity, reverse parking sensor technology is evolving toward greater precision, intelligence, and integration.

In terms of precision improvement: Future ultrasonic sensors may further optimize their frequency and signal processing algorithms to reduce interference from environmental noise (such as the low-frequency noise from engines and exhaust pipes observed in this test). This will minimize distance measurement errors, enabling stable operation even under complex road conditions.

In terms of intelligent integration: Reverse parking sensors are expected to achieve in-depth synergy with other sensors such as cameras, millimeter-wave radars, and lidar, forming a multi-sensor fusion parking assistance system. Through data complementarity, this system will not only more accurately identify obstacle types (e.g., pedestrians, walls, low-lying objects) but also combine with vehicle dynamics models to provide drivers with more intelligent parking recommendations, or even assist in automatic parking operations.

Furthermore, with the popularization of new energy vehicles, reverse parking sensors may undergo adaptive optimization to match the characteristics of electric vehicles. For instance, considering the quiet driving nature of electric vehicles, the frequency and rhythm of alarm sounds could be adjusted—ensuring drivers can clearly perceive alerts while avoiding unnecessary disturbance to nearby pedestrians.

Having dedicated years to the field of acoustics, Beijing Allinby will continue to optimize its measurement systems and deepen acoustic research. It aims to provide accurate data support for the innovative development of technologies such as reverse parking sensors, contributing to the continuous upgrading of automotive safety technologies and safeguarding safer travel for more people.