Radar is the method of radio to detect targets and determine their spatial position. Thus, radar is an electronic device that uses electromagnetic waves to detect targets. The radar emits electromagnetic waves to irradiate the target. It receives its echoes, thereby obtaining information on the distance, rate of change of space, bearing, and altitude from the target to the point of electromagnetic wave emission.
The so-called millimeter-wave radar is a radar that works in the millimeter-wave band. The range measurement principle is the same as that of a general radar, that is, radio waves (radar waves) are sent out, then the return waves are received, and the target’s position data are measured according to the time difference between sending and receiving. Millimeter wave radar is the frequency of this radio wave is millimeter wave, frequency band.
Millimeter-wave radar is by far the most important detection component in vehicle detection radar, millimeter-wave radar and other sensors compared, with high operating frequency, short wavelength, with high resolution, while having all-weather measurement capabilities, compared to the weather impact factors are small, rain and snow conditions can still be used normally, especially suitable for vehicle use.
Millimeter wave radar has been used in high-end cars since the last century, and the technology is relatively mature. The wavelength of the millimeter wave is between the centimeter wave and the optical wave, so the millimeter wave has the advantages of both microwave guidance and optoelectronic guidance, and its guidance head has the characteristics of small size, light mass, and high spatial resolution. In addition, the millimeter-wave guidance head has the ability to penetrate fog, smoke, and dust, which is a major advantage compared to LIDAR.
The disadvantages of millimeter wave radar are also very intuitive, the detection distance is directly constrained by the frequency band loss (to detect far, you must use a high-frequency band radar) and the inability to accurately model all surrounding obstacles.
Millimeter wave radar application manufacturers – a typical representative of Tesla.
Autopilot 2.0, a set of hardware, in addition to 8 cameras and 12 new ultrasonic sensors, a forward detection radar caught our attention. Upon research, the detection radar used on Tesla is a millimeter wave radar, not the laser mines used in other mainstream driverless R&D.
According to the current mainstream classification, automotive millimeter-wave radar frequencies mainly include 77GHz and 24GHz, of which the former has a shorter wavelength and longer detection distance, so it is mainly used for forwarding vehicle detection; while the latter is usually used for detection around the vehicle, such as blind spot detection. In addition, there are also some other frequency bands of millimeter wave radar, such as 60GHz in Japan and 79GHz used in Taiwan.
From the whole millimeter wave radar industry development, no matter system or device, the core technology is still in the hands of foreign enterprises, such as Bosch, Continental, Delphi, etc. in the system field, and Freescale, Infineon, STMicroelectronics, etc. in the device. However, in recent years, the domestic also emerged a number of millimeter wave radar-related companies, accelerating the development of the industry. Some experts believe that compared to the fierce competition on the camera side, millimeter wave radar is more innovative, with more potential market space and more opportunities.
Especially 77GHz, the future is expected to become the mainstream of millimeter wave radar, and in the country, accelerate the development of domestic 77GHZ millimeter-wave radar chips and as soon as possible vehicle applications will be China’s automotive millimeter-wave radar industry opportunities.
77G millimeter wave radar system
When driving a car by the rearview mirror alone often can not see the left and right blind spots of the vehicle, you need to turn your head to observe to ensure safety, easy to cause collision hazards. In order to eliminate the visual blind spots, the blind spot monitoring system emerged.
In order to eliminate the visual blind spot, a blind spot information system (BLIS) was invented to overcome the above-hidden dangers. At present, all major car brands basically have similar products, most of which are equipped with high-grade cars.
As there is a visual blind spot in the rearview mirror of the car, the vehicle in the blind spot cannot be seen before changing lanes, and if there is an overtaking vehicle in the blind spot, a collision will occur when changing lanes. In heavy rain, and foggy weather, the night light is dim, more difficult to see the vehicle behind, and when changing lanes will face greater danger, a blind spot monitoring system is to solve the blind spot of the rearview mirror and produced. The blind spot monitoring system also called lane assist system, BSM or BLIS for short is a safety class of high-tech configuration on the car, the main function is to remove the blind spot in the rearview mirror, through the microwave radar detection of the vehicle on both sides of the blind spot in the rearview mirror overtaking vehicles, to remind the driver, so as to avoid accidents in the process of changing lanes due to the blind spot in the rearview mirror. Many models currently on the market are equipped with the blind spot monitoring feature.
The blind spot monitoring system through the device in the rear of the body inspection bar within the two 77GHz radar sensors, in the vehicle driving speed is greater than 10KM / H automatically starts, real-time to the left and right 3 meters rear 50 meters range, send out detection microwave signal to detect the scanning vehicle sides and rear area, to avoid the risk of dead ends, for driving escort.
When the detection of vehicles in the blind spot is within 77 meters and the two vehicles’ collision time is shorter than 3.5 seconds when the light flashes to warn the driver. Throughout the whole driving process, uninterrupted detection and reminding, prevent traffic safety accidents caused by bad weather, driver negligence, blind spots in the rearview mirror, newcomers to the road, and other potential dangers during the driving process. Rainy days also do not have to be afraid, the system is not struck.
Rainy day driving, this time the rear-view mirror is completely blurred by rain. The yellow light of the blind spot monitoring system becomes an excellent guiding tool for merging, even if the entire rearview mirror is blurred out, relying on the yellow light of the blind spot warning system can still clearly determine the road conditions behind. When there is a car quickly overtakes, the yellow light flashes; when there is a car behind, the yellow light is on, this time the blind spot monitoring system can basically replace most of the mirror function.
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