LIDAR is set to drastically change the world and how we drive. Here’s how it works

Libby Plummer Read more August 4, 2017

LIDAR technology has been around for decades and used in everything from spacecraft and robots, to speed guns. It also happens to be one of the technologies driving the development of autonomous vehicles.

Driverless cars may not be a widespread reality on the roads just yet, but if they are ever to become truly mainstream, LIDAR will be one of the onboard technologies that make them possible and keeps passengers safe.

What is LIDAR?

A portmanteau of light and Radar, LIDAR is also an acronym for Light Detection and Ranging, or Light Imaging, Detection and Ranging. The technology was first developed in the early 1960s.

Put simply, LIDAR bounces light off objects to see where they are, just as radar uses radio waves and sonar uses sound. LIDAR systems send out pulses of light outside of the visible spectrum and time how long it takes for them to bounce back. The time it takes for the light to reflect back tells the sensor how far away it is and reveals its shape.

The direction and distance between the sweeping LIDAR sensor and each detected object are then plotted on a 3D map called a ‘point cloud’ in order to build up a detailed picture of the surroundings. While radar works well over long distances, and sonar is better suited to short distances, LIDAR provides a handy middle ground.

What is LIDAR used for?

Because of its ability to examine with extreme accuracy and flexibility LIDAR has a wide number of uses, in particular, the production of high-resolution maps. As well as surveying, LIDAR has been used in agriculture, archaeology, and robots. The technology’s first big break into the public consciousness was when the crew of the Apollo 15 lunar mission used a laser altimeter to map the surface of the moon.

While the technology will continue to be used in a variety of fields, it’s set to be a big player in the future of driverless cars, acting as the vehicles’ ‘eyes’.

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How is LIDAR used in driverless cars?

While early LIDAR technology was slow and bulky, the development of faster computing speeds and smaller electronics means it’s now much more swift and can be more easily integrated into existing technology. In driverless cars, the technology works in tandem with other sensors and onboard cameras to monitor what’s going on around the vehicle.

LIDAR is essential thanks to its ability to detect obstacles and draw an instant virtual picture of the surroundings. The 3D image map that’s created enables the vehicle’s onboard processor to differentiate between various objects including different vehicles, road markings, and people. This can affect how the cars safely navigate the roads – whether that’s slowing down, or taking evasive action.

Does LIDAR have any limitations?

LIDAR is not without its faults. A 2015 research paper claimed that the LIDAR systems on driverless cars could be thwarted by a simple laser pointer. It found a low-power laser and pulse generator could fool a car into believing other cars and pedestrians are around it. This gaping vulnerability could lead to cars being stopped suddenly in the middle of the road if they sensed what they believed to be another car or a pedestrian.

LIDAR can also be affected by bad weather, which slashes the range and accuracy of the sensors.

With the technology playing such a vital role in the future of driverless cars, the stakes are high. Earlier this year, Google’s self-driving car project Waymo sued Uber for allegedly stealing plans for its LIDAR technology, while Google parent company Alphabet later dropped three of the four patent claims it made, the proceedings are ongoing as of August 2017.

However, not everyone agrees that LIDAR is essential. So far, Tesla has opted not to use LIDAR in its cars and instead relies on a radar-based system along with cameras.