Millimeter-Wave Radar for Automotive Applications

Key Takeaways

• In the automotive industry, mmWave radar is employed for the accurate sensing of the location, velocity, and angle of objects.

• Automotive mmWave radar can be classified into three types based on the frequencies utilized: 24GHz, 77GHz, and 79GHz, respectively.

• MmWave radar is employed along with two cameras in the automatic braking systems of automobiles.

Millimeter-wave radar is a key component of advanced driver assistance systems and autonomous vehicles

Different types of sensors are employed in industrial, commercial, civilian, and automobile applications to aid in intelligent decision-making and promote safe operation. Among the various sensors, millimeter-wave (mmWave) radar for automotive applications is critical to enabling the production of intelligent vehicles. Millimeter-wave radar enables a safe and convenient driving experience and is a primary part of advanced driver assistance systems and autonomous vehicles. Let’s explore the role millimeter-wave radar plays in automotive applications. 

Advanced Technology for Automotive Systems

The fatalities caused by road accidents are numerous and devastating. Advanced driver assistance systems and autonomous vehicles were developed to enable a safer driving experience. Different advanced technologies have been developed to build these two innovative automotive systems. Some of those new technologies include:

1. Sensors such as radar, liDAR, and optical cameras.
2. High-speed information processing systems and automotive Ethernet networking.
3. Powerful digital signal processing and high precision navigators.
4. Communications such as vehicle-to-vehicle, vehicle-to-network, and vehicle-to-grid. 

Let’s discuss the use of radio detection and ranging for automotive applications, emphasizing the use of millimeter-wave radar. 

Radar for Automotive Applications

Automotive systems use optical cameras, liDAR, and radar for detection and ranging. Automotive radar is the most reliable sensor technology; it can detect distance to the object and motion while providing information such as velocity and angle. Automotive radar utilizes radio waves to detect obstacles. The data obtained from radar systems require low signal processing, which makes radar even more attractive.

The advantages of automotive radar can be summarised as:

1. Reliable under any environmental condition
2. The detection range is longer than other sensor technologies
3. Lightweight and small in size

There are different types of radar used for automotive applications. Millimeter-wave (mmWave) radar is popular due to its stable detection of targets no matter how bad the atmospheric conditions are. 

Millimeter-Wave Radar for Automotive Applications

Millimeter waves are short-wavelength electromagnetic waves within the frequency range of 30-300GHz. The wavelength of millimeter-wave radar varies from 1 millimeter to 1 centimeter. In the automotive industry, millimeter-wave radar is employed for the accurate sensing of location, velocity, and angle with no interference. This radar plays a critical role in advanced driver assistance systems and autonomous driving. 

How Does Automotive Millimeter-Wave Radar Work?

Millimeter waves are transmitted by automotive millimeter-wave radar. When these waves hit an object in their path, the waves are reflected back to the radar, enabling detection. Multiple antennas in the mmWave radar capture the reflected signal. By processing the time of flight of these mmWave pulses, the distance to the target, angle of arrival, and relative velocity are determined. From the information obtained through the processing of the reflected signal, mmWave radar is capable of determining the position and motion of an object.

Automotive Millimeter-Wave Radar Types

Automotive millimeter-wave radar is used in the  following systems of a vehicle:

1. Automatic emergency braking systems

2. Blindspot detection

3. Forward collision warning systems

4. Adaptive cruise control

5. Parking assistance

Automotive millimeter-wave radar can be classified into three types based on the frequencies utilized: 24GHz, 77GHz, and 79GHz, respectively.

1. 24GHz mmWave radar: 24 GHz mmWave radar is called short wave radar. Short wave radar senses the distance in the range of 15cm to 30m and is used for parking assistance. 

2. 77GHz mmWave radar: Blindspot detection requires detection in the medium range of 1m to 100m and 77GHz mmWave radar is used for this purpose. This radar is not applicable within the interior of an automobile. 

3. 79GHz mmWave radar: Adaptive cruise control and the forward-collision warning system requires detection up to 250m. 79GHz mmWave radar is incorporated to achieve this long-range detection. 

The Use of Millimeter-Wave Radar in Automatic Braking Systems

MmWave radar is employed along with cameras in the automatic braking systems of automobiles. Cameras are used for recognizing the forward curve radius and obstacles. They also control the mmWave radar detection direction. The distance and approaching speed of an obstacle are detected by mmWave radar. It warns the driver about the obstacle and triggers automatic braking.

The millimeter-wave radar used in automotive applications is designed to correctly distinguish between multiple obstacles. The beam steering functionality is introduced in mmWave radar systems to remove unwanted information from desired detection information.

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