With some notable exceptions, such as Tesla, there is general agreement among Level 4 or Level 5 autonomous driving companies that the holy trinity of cameras, radar, and LiDAR sensors is required to develop a truly safe driverless car.
More recently, LiDAR has also been part of the sensor array for automakers developing advanced driver assistance systems (ADAS), such as the Level 3 Drive Pilot system available on the latest Mercedes-Benz S-class and EQS.
Luminar is a relatively new startup that specializes in developing LiDAR technologies suitable for use in ADAS systems and eventually autonomous vehicles. Most recently, Volvo announced that it will use Luminar’s LiDAR system as part of the safety and ADAS for its next-generation EX90 large SUV.
So what is LiDAR and how does Luminar technology differ from the standard?
What is LiDAR?
LiDAR (light detection and ranging) is a system for detecting objects and the distance to them using a laser with an infrared wavelength that is outside the limits of human vision.
Although the concept of LiDAR has been around since the 1960s and has been used in aerospace applications since the 1970s, the technology has only entered the automotive field in the last 30 years.
In the 1990s, LiDAR-based adaptive cruise control systems were offered on various Japanese domestic market vehicles such as the Mitsubishi Debonair and Diamante (the latter related to the Mitsubishi Magna/Verada), as well as the Toyota Celsior, a rebadged Lexus. LS.
Over the past 10 years, LiDAR technology for automotive applications has improved significantly in terms of LiDAR sensors’ resolution (ie, how accurately an object’s shape and size can be determined) and their range (the maximum distance at which they can detect objects).
Along with other advances, this has also allowed LiDAR to play a role in more advanced automated driving systems, such as traffic assistants.
Who is Luminar?
Luminar was founded in 2012 by 17-year-old prodigy Austin Russell. Focusing on significant state-of-the-art innovation, the company initially attempted to develop its technology without much publicity, adopting a strategy of developing and manufacturing key LiDAR sensor components in-house rather than purchasing off-the-shelf parts.
One of Luminar’s high-profile announcements that gained more recognition in 2017 and 2018 was its partnership with the first major car manufacturer, Toyota, through the Toyota Research Institute (TRI). TRI has chosen to use Luminar’s LiDAR system as part of the sensor suite in its Platform 2.1 autonomous test vehicles, fleet Lexus LS sedans modified to install many different sensors.
Today, the company is headquartered in Orlando, Florida and has more than 400 employees along with its own factory. In 2020, it became a public company and trades under the symbol Lazr on the Nasdaq. Its current market capitalization is around US$2.76 billion (AU$4.3 billion).
Key innovations and technologies
Luminar’s focus on the automotive industry means that its key innovations are focused on making LiDAR safe, accurate and reliable with a wide field of view, while being affordable for car manufacturers.
Technically, this has led to three key areas of innovation, namely the wavelength, the ranging method used (how the LiDAR measures the distance to the objects, or ‘pixels’ that have been reflected back), and the field coverage method (ie how the LiDAR distributes light and creates a three-dimensional spatial image of the environment).
Conventional lidars use near-infrared wavelengths around 905 nm (nanometers), which, although invisible, can still pose a hazard to human vision. This limits the power of the laser that can be used, thereby compromising other factors such as the maximum range of the LiDAR.
In contrast, Luminar chose to use a design with a longer wavelength of 1550 nm, which, qualifying as a Class 1 laser, poses minimal eye hazards and thus allows Luminar to increase the power of its laser to provide longer range detection.
Another innovation is the direct time-of-flight technique that Luminar’s LiDAR uses as a ranging method.
To determine the distance to the object, a strong but short pulse of light (typically about 100 photons with a pulse duration of 2 to 15 nanoseconds) is emitted. Luminar claims this enables very high speed measurements, eliminating speed-dependent ranging errors, and the ability to distinguish between light reflected from physical objects or light reflected or scattered by atmospheric conditions such as fog.
Therefore, the company claims that for automotive applications, these advantages make the direct time-of-flight measurement process superior to alternatives such as single-photon detection or frequency-modulated continuous-wave (FMCW) methods, which require more time for accurate measurements.
Finally, Luminar decided to combine the above technologies with a dual-axis scanning mirror as a way to distribute the light. Luminar claims this method offers the best balance between cost and durability, with less exposure to temperature, vibration and other shocks, and is cost-effective to manufacture and provides economies of scale.
The firm notes that other technologies, such as microelectromechanical systems (MEMS) and silicon photonics, are more expensive to manufacture or less robust and more sensitive to temperature changes.
Users of Luminar technology
Luminar claims to have partnerships with more than 50 commercial entities, including several major car manufacturers such as Mercedes-Benz, Volvo/Polestar and Nissan. Luminar is also a supplier to other automotive vendors, including Intel’s Mobileye, and provides Nvidia with its Iris LiDAR system as part of its “Drive Hyperion” autonomous driving platform.
Perhaps the most notable debut of Luminar technology will be the use of the LiDAR system in the the upcoming Volvo EX90marking the launch of its technology on a production vehicle sold worldwide.
Volvo claims that using Luminar’s LiDAR sensor will allow it to detect pedestrians up to 250m in front of the car, and be able to distinguish a tire on a dark or black road up to 120m in front of the car.