LIDAR

LIDAR (a.k.a LiDAR or Lidar) is a developing technology commonly used in autonomous vehicles. LIDAR commonly stands for “light detection and ranging” or some variation of that. Like sonar and radar, LIDAR uses echolocation to develop an “image” of the devices surroundings. In order to create this image, LIDAR uses lasers to send out light pulses and tracks how long it takes for the lights to bounce back. Charles Townes and Arthur Schawlow are thought to be the some of the first people to theorize the modern LDIAR in 1958.

 

Why LIDAR?

Radar and sonar are both great tools that for creating a map of local surroundings, but both have limitations. Radar uses radio waves but has limitations in short distances. Sonar, using sound waves, is limited in long range uses. LIDAR works well in both long range and short range, making it a great tool for self driving cars, which need to map obstacles and objects on the road far and near.

 

How does LIDAR work?

As described above, LIDAR units emit a light pulse and count how long it takes for the pulse to return. This echolocation information is coupled with GPS coordinates and a inertial measurements unit (IMU), which measures tilt and angle, allows for a computer to compile an image of the surrounding area. As you can see from the image below, once all the data is complied LIDAR produces a clear, comprehensive image. These images were created by a LIDAR sensor on a National Oceanic and Atmospheric Administration aircraft flying over Bixby Bridge in California.

The above video, from 2011, shows how LIDAR can be used with autonomous vehicles to map their surroundings. It allows the cars to “see” all obstacles around the car and allow an autonomous vehicle to navigate around the obstacles.

 

People Using LIDAR for Autonomous Vehicles

LIDAR is not new to cars. It has been used for various reasons and can be found on many vehicles today. In 1992, Mitsubishi used LIDAR technology for distance warning, and since then, many other auto manufacturers have followed suit and further developed the technology. LIDAR is used as the base technology for many adaptive cruise control systems that are seen on the road today. As more automation comes to cars, LIDAR is seen by some as one of the most important technologies for fully autonomous vehicles. Google and Uber are two of the biggest names using LIDAR in their development of autonomous vehicles, and Velodyne is a company at the forefront of further development in LIDAR technology. These LIDAR sensors can be seen on the tops of vehicles scanning the surrounding area.

 

Limitations for LIDAR in Self Driving Cars

Although LIDAR is seen as essential by many people for fully autonomous vehicles, it does have many limitations. Snow and fog have been found to hinder LIDAR’s ability as well as any object that could block the sensor.  Another hurdle for LIDAR is the expensive costs associated with the technology. Although some LIDAR systems can be made for low cost, the systems needed for autonomous driving can be well beyond $10,000, with Velodyne’s top sensor (being used by Google and Uber) selling for $80,000. These price tags will inhibit the adoption of LIDAR technology if auto manufacturers attempt to make autonomous vehicles for the masses in the near future. Elon Musk, head of Tesla, has remarked the he thinks LIDAR is unnecessary for autonomous vehicles and has therefore not incorporated LIDAR in Tesla’s autonomous vehicle development.

 

Other uses of LIDAR

  • Mapping Forests
  • Police Speed Trap Guns
  • Mapping coastline
  • Apollo 15 mission
  • Video Game mapping of real life racing tracks

 

Sources:

  • http://gisgeography.com/lidar-light-detection-and-ranging/
  • https://techcrunch.com/2017/02/12/wtf-is-lidar/
  • https://www.technologyreview.com/s/603885/autonomous-cars-lidar-sensors/
  • https://oceanservice.noaa.gov/facts/lidar.html

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