In 2019, as the automotive ADAS technology begins to evolve to unmanned vehicle technology, more sensor technologies will be cited.
Technologies such as millimeter wave radar, laser radar (LiDAR) and inertial measurement components will be introduced to the test vehicle so that the vehicle can better obtain external information and make accurate and rapid decisions.
The three sensor improvement areas for autonomous vehicles are millimeter wave radar, lidar and inertial measurement unit
“To some extent, we may see these technologies implemented in vehicles in restricted environments, such as robotic taxis in geo-fenced areas,” pointed out Chris Jacobs, vice president of autonomous driving and automotive safety at Analog Devices. “Or only test in an environment with good weather conditions.”
The new technology has a significant improvement over the existing sensor system. They include:
Millimeter-wave radar: Millimeter-wave radar usually works in the 77/79 GHz range and can accomplish things that ordinary 24 GHz radar sensors cannot do. The most important thing is object recognition.
“Radar usually tells you that something exists, but you can’t know if it is a bicycle, a person or a semi-truck,” Jacobs said. “Millimeter wave radar allows you to start distinguishing these things.”
Developers of self-driving cars think this is an important first step, because after the use of millimeter wave radar, object recognition is faster, for example, if the vehicle recognizes a pothole in its path, it can take earlier evasive actions.
Millimeter-wave radar also enables the vehicle to calculate the tangential velocity of obstacles entering its path, allowing it to determine whether a collision is imminent. Jacobs said that traditional radars cannot do this. “We need to allow more reaction time for the car, so we think millimeter wave radar will become the key.”
1500nm LiDAR: The next-generation LiDAR systems will use a light wavelength of 1,500 nm instead of the traditional 900 nm wavelength, allowing them to see farther objects.
“It will be four times the detection range of today’s lidar.” Jacobs said: “You can see a tire or a piece of wood on a road of 150 to 200 meters. And you will be able to make subsequent predictions faster.”
At present, the most important issue of LiDAR is cost. The new generation of LiDAR adopts more expensive radar systems. In addition, its photodetector is manufactured on a 2-inch diameter gallium indium wafer, which is not suitable for automotive-scale production.
Jacobs believes that 1500nm technology is a more effective sensor in the future. He said this is why many OEMs are now investing in this technology. “You may not see the active deployment of 1,500nm technology in 2019, but soon, we will start to see some new applications appear.”
Autonomous inertial measurement unit: Inertial measurement units (IMUs) that use gyroscopes and accelerometers have long existed in vehicles, but automakers have begun to create new IMUs for autonomous vehicles.
The key advantage of these automatic IMUs is to enhance the ability of dead reckoning and measurement. When other systems of millimeter wave radar, lidar, and GPS are unstable, dead reckoning is the key to the car’s “seeing” the way forward. For example, this is the case when a vehicle moves from a sunlit environment to a dark tunnel. At such moments, radar and lidar may be unstable for a fraction of a second, and GPS reception may be lost. However, with advanced acceleration-based IMUs, the vehicle will not lose its direction.
The key difference between the new IMUs and the existing IMUs commonly used in Electronic stability control is their offset drift. Compared with the current automotive-grade IMU, the new IMU drift will be more stable and the route will be more stable.
Jacobs said this difference can save lives. “We believe that keeping your car moving in the lane in the presence of unstable sensor sensors is absolutely vital. With the new sensor, even if all external input is lost, it can still maintain sufficient accuracy. .”
“These tests will give the public the opportunity to actually see the application of the technology. This is a very important step because it directly involves consumers’ acceptance of advanced technology. There must be sufficient practical evidence to prove that these technologies can work. , And we need to demonstrate their effects in a safe way.” Jacobs said.