Lidar Explained

You’ve probably heard reference to “lidar.” Here’s where you can get a quick tutorial

By Gary S. Vasilash

Elon Musk once famously said, “Lidar is a fool’s errand.”

And it went downhill from there.

What was he talking about?

A sensor that uses laser beams.

The sensor sends out pulsed light waves from as many as 128 individual lasers (at an eye-safe frequency, so you need not worry about being blinded by a vehicle coming at you with lidar engaged). The waves hit something and bounce back. The time is calculated (send, hit, return). And the information is used to generate a 3D map of the environment. Realize that there is a lot going on here: this beam bouncing is taking place at a rate of millions of times per second.

Using lasers for sensing. (Image: Velodyne Lidar)

The whole purpose of this is to enhance a vehicle’s ability to be able to provide safer driving—for the people within the vehicle as well as others, be they in other vehicles or on foot. And it can also contribute to self-driving vehicles, with the sensor or sensors (there are some lidar devices that have a 360° view so conceivably only one would be needed on the roof of a vehicle to “see” what’s going on; there are some devices that have more limited view, say 120°, so there would be multiples installed) providing input so that the vehicle can perform accordingly.

3D lidar was invented by David Hall in 2005. He had established a company in 1983 to produce audio subwoofers. What was then Velodyne Acoustics has become Velodyne Lidar.

And on this edition of “Autoline After Hours” Mircea Gradu, Velodyne senior vice president of Product and Quality, provides an explanation of lidar—the how, why, where and when of the technology.

One of the things that he really emphasizes in his comments is the importance of lidar when it comes to safety.

He points out, for example, that most vehicle-pedestrian accidents occur after dark. In 2018 76% of pedestrian crash fatalities in the U.S. occurred at night.

Lidar can “see” in the dark. Camera-radar based system don’t have the same level of capabilities. So so far as Velodyne is concerned, any advanced driver assistance system (ADAS) really needs to have lidar sensors as part of its sensing suite. Assuming that the vehicles are going to travel at night.

While Gradu is, not surprisingly, a bit proponent of lidar, he also acknowledges that there needs to be sensor fusion–the use more than just one or two types of sensors. After all, the subject is safety, and who wants to stint?

Gradu talks with Alexa St. John of Automotive News, “Autoline’s” John McElroy and me.

Then during the second half of the show the three of us discuss a number of topics, including the semiconductor shortage and potential solutions, whether companies like GM are putting billions of dollars at risk when they invest heavily in electric vehicles and more.

And you can watch the show right here.

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