Intelligent Driving: Ultrasonic Radar

Ultrasonic radar is one of the indispensable sensors in autonomous driving, especially for automatic parking and short-distance sensing during driving. These applications are the first to be implemented in autonomous driving and are also rigid needs.

Especially automatic parking. The screenshot I posted on WeChat Moments a few days ago was of Tesla’s ADAS software upgrade package, which cost $32,000 and did not include the automatic parking function.

Since we are going to talk about ultrasonic radar today, first we need to know what ultrasonic waves are. Although ultrasonic waves also have frequency and wavelength, they are different from the electromagnetic waves we are familiar with and used in the field of communication. Ultrasonic waves are sound waves and mechanical waves. To propagate, they must have a propagation medium and cannot propagate in a vacuum. The propagation rate of ultrasonic waves is the same as that of sound waves, which is about 340m/s in the air. The frequency is generally higher than 20kHz, and the wavelength in the air is generally shorter than 2cm. Because the frequency exceeds the hearing range of the human ear, it is called ultrasonic.

The principle of using ultrasound for distance measurement and positioning is the skill that bats need to fly at night. Bats emit ultrasound in the form of pulses and perform echolocation by receiving reflected echoes. This basic principle of echolocation is applicable to laser, millimeter wave, and ultrasound, and is generally referred to as radar.

Regarding the history of ultrasonic radar being used in cars, the common saying in China is that in the 1960s, when Tony Hayes was researching ultrasonic blind guidance equipment, he discovered that ultrasonic technology should be very suitable for car reversing assistance. But when he confidently promoted this invention to British Jaguar executives, he was dismissed by Jaguar executives with a fixed mindset. Jaguar executives believed that drivers have two eyes to judge distances, so why would normal people need radar, so the invention was abandoned. Now, this should be a typical example of a fixed mindset. Ultrasonic radar has almost become a standard feature of cars, and Jaguar executives, with the mentality of experienced drivers, misjudged the new needs of future drivers.

For example, automatic parking and lateral distance sensing during vehicle driving are the most typical applications of ultrasound in advanced driver assistance systems (ADAS). Automatic parking systems are generally equipped with 12 ultrasonic radars, including 8 UPA ultrasonic radars installed in front and behind the car, and 4 APA ultrasonic radars installed on both sides of the car.

UPA ultrasonic radar, Ultrasonic Parking Assistant, has a higher frequency, 58kHz, high accuracy, and a shorter sensing distance. APA ultrasonic radar, Automatic Parking Assistant, has a lower frequency, 40kHz, and average accuracy, but a longer sensing distance, generally more than three meters. Therefore, the process of automatic parking is to use ultrasonic radar to sense the surrounding environment when the car is cruising at low speed, find an empty parking space, and automatically park the car in the parking space. In addition, the application of lateral sensing is mainly used to remind the distance of vehicles in parallel lanes during vehicle driving.

Ultrasonic radar is a relatively mature industry. The industry chain includes ultrasonic radar sensors and ultrasonic reversing radar systems. Radar system manufacturers are mainly tier 1 manufacturers, such as Bosch, Valeo, Tongzhi, etc. Ultrasonic radar sensor manufacturers include Bosch, Japan Murata, Nicera, etc. The leading domestic company is Audiwei, a NEEQ company, with automotive electronics-related revenue of 109 million in 2020. In terms of shipments, Audiwei's on-board ultrasonic sensors account for 9% of the global passenger car market share. Since ultrasonic radar technology is so mature, are there any investment opportunities? Although everyone understands the technical principles of ultrasonic radar and can make products, the gap between domestic manufacturers is mainly reflected in the stability and reliability of the products, that is, the gap between high-end and low-end products, which is also the core barrier of automotive-grade products. From this perspective, domestic manufacturers still have opportunities for domestic substitution.