At 1:34 PM on July 26, 1971, the Saturn V rocket took off from the Kennedy Space Center, marking the beginning of the Apollo 15 mission. It was the first time a lunar rover was involved in space mission, and over the course of 67 hours, it went out three times and traveled 27.9 kilometers. It was also the first mission to ever use LiDAR. This technology, first conceived in 1930 by the Irish physicist Edward Hutchinson Synge, makes it possible to measure an object from a distance.
On this occasion, it allowed man to map the moon. As NASA scientist Dr. James Abshire explains, “LiDAR was based on a ruby laser pumped by a flash lamp, and the Apollo 15-17 missions used it to make several thousand measurements of the height of the lunar surface from the orbit.” It could do this because – unlike radar, which uses radio waves, or sonar, which uses acoustic waves – LiDAR uses light waves.
That’s where the name comes from: by combining the terms “light” and “radar.” The British physicist James Ring explains this in his book, The Laser in Astronomy, published in 1963. The technology was developed off the back of the American physicist Theodore Maiman’s invention of the laser. Back then they were mainly used for meteorological purposes, but even then, scientists could tell they were destined for greater things. “Since its invention just three years ago, the laser has stimulated the imagination of scientists in virtually every field,” reads the September 1961 issue of the Bulletin of the American Meteorological Society. “Unusual laser beams have opened up the possibility of searching unexplored areas in the broad spectrum of electromagnetic radiation. The laser now makes it possible to exploit the energy of the electromagnetic radiation and the shape its optical properties.”
As early as the 1970s, the word “LiDAR” was understood to be an acronym for “Light Detection And Ranging,” or “Laser Imaging Detection And Ranging.” In the 1980s, the advent of diode pumped lasers significantly improved the efficiency and resolution of the technology.
“These advances have been used in NASA’s space missions to map the shape and topography of Mars with more than 600 million measurements, demonstrate initial measurements of the Earth’s topography, and measure the detailed shape of its asteroid,” says James Abshire. “Orbital lidar has also been used in experiments to demonstrate laser distance over planetary distances, including the transmission of laser pulses from the Earth to the orbit of Mars. Based on the proven value of these measurements, LiDAR is now the preferred measurement approach for many new space missions.”
But that’s not all LiDAR does. After making itself indispensable to astronomers, LiDAR has revolutionized archeology and accelerated the development of self-driving cars, among other feats.
The first attempts to apply LiDAR to archeology took place in Europe in the 2000s. Today, a month doesn’t go by without there being some kind of new discovery thanks to the technology. This month, it uncovered thousands of Mayan building hidden deep in the Guatemalan jungle for centuries. The vegetation was no obstacle to airborne LiDAR, which can detect the most minute details, including those under the thickest of forest canopies. The set of points it recorded while it flew over the area was filtered using powerful algorithms that made a 3D model of the terrain, using photogrammetry. The map covered 2,100 km2 of the north of the Peten department and covered the Mayan biosphere reserve created in 1990.
All in all, 60,000 Mayan structures were revealed. Pyramids, palaces, ceremonial centers, as well as agricultural terrains and dwellings, forming in total “a dozen cities.” “The irrigated terraces and fields, the fortified sites and the big roads reveal how the Mayans changed the natural landscape on an incredible scale,” says Francisco Estrada-Belli, professor of archeology at Tulane University. “The Mayan wars have been researched for decades, often focusing on the collapse of classical sites,” said Thomas Garrison, professor of archeology at Ithaca College. But “LiDAR revealed the physical manifestation of these past conflicts in a way that shows that they were a determining factor in the ancient Mayan culture, and that they probably shaped the emergence and development of some of their biggest cities,” he says.
In addition to this astounding discovery, LiDAR has made it possible to reveal the existence of a lost city in Mexico, which contained, at its height, as many buildings as Manhattan; Khmer cities hidden in the Cambodian jungle; as well as a Viking fortress in Denmark from the tenth century.
By surveying forests’ structures and topography, LiDAR also makes it possible to develop models to predict how they’ll evolve. The technology is widely used to both observe and manage forests. It will also allow the United Kingdom to map its entire territory by 2020. “This ambitious project will improve our understanding of England’s natural features and unique landscape, helping us better understand flood risks, plan effective defenses and fight against waste,” says UK Environment Agency Director James Bevan. “I am pleased that we are able to collect, use and share such valuable data to help improve the environment and its conservation.
But far from the forests, jungles and green hills of the English countryside, LiDAR seems to be especially essential in urban environments, where it serves as self-driving cars’ eyes.
According to a 2016 report by the firm Frost & Sullivan, around 90% of the self-driving car industry’s projects rely on this technology to detect obstacles and produce an accurate picture of the road. So it was no surprise that LiDAR was at the heart of the legal dispute between Waymo, Google’s self-driving vehicle subsidiary, and Uber. Waymo accused Uber of recruiting its star engineer, Anthony Levandowski, to benefit from its LiDAR-related industrial secrets.
The dispute was ultimately settled amicably on February 9. Because there was no cash penalty, the deal did not jeopardize Uber’s self-driving vehicle program, but it also prevented it from catching up to Waymo. Most other competitors are also trying to catch up when it comes to LiDAR. General Motors acquired the manufacturer Lidar Strobe in October 2017. That same month, Ford bought the startup Princeton Lightwave through its subsidiary Argo AI.
The only notable outlier in the industry, Tesla prefers a combination of radar, cameras and ultrasonic sensors. “[LiDAR] is a crutch that will make manufacturers feel too comfortable, to the point where they won’t be able to give it up,” says CEO Elon Musk. “Maybe I’m wrong and going to look like an idiot. But I’m pretty sure of myself.” And to be sure, Tesla’s cars already offer features similar than those found in self-driving vehicles. Under the “Autopilot” option, they take orders under certain conditions.
According to Elon Musk, Tesla still needs to “solve the problem of passive optical recognition for autonomous driving in all environments and conditions” but, he says, “using active optics like LiDAR, which are unable to read signs, makes no sense. It’s expensive and it will just make the product more expensive.”
LiDAR is a particularly expensive technology. Some pieces can cost between 70,000 and 80,000 euros. This is totally incompatible with vehicles’ mass commercialization. Manufacturers are aware of this, and they are working on initiatives to divide their production costs. Velodyne LiDAR has reduced the cost of its VLP-16 Puck by 50% by taking advantage of advanced and streamlined manufacturing techniques at its plant in San Jose, USA. “With this reduction in costs, we will be able to provide more Pucks to more customers, support the growing number of self-driving vehicle development fleets around the world, and start creating a brighter future,” says the company’s CEO, David Hall. “Our goal is to democratize transportation security by making it accessible to every man, woman and child in the world as quickly as possible.” Doing so would also allow it to stay at the forefront of a market that could well value 13 billion dollars by 2027.
In any case, LiDAR and its pulses of infrared light will continue to push research and innovation for a long time, and its unique images will continue to fire up our imagination. Some creators have already taken it up, like Radiohead did in its “House of Cards” music video, or the video game development studio Introversion Software for its disturbing Dark Sombre game.
How many more wonders will it uncover? How many more machines will it endow with sight?