What is lidar?

Lidar, short for light detection and ranging, is a way of measuring the world with lasers. A lidar sensor fires pulses of laser light, times how long each takes to reflect back, and turns that into a distance. Repeat that millions of times per second and you get a "point cloud": a precise 3D picture of everything around the sensor.

How it works

1. The sensor sends out pulses of laser light, usually invisible near-infrared.
2. The light hits objects and bounces back.
3. The round-trip time gives the distance to each point.
4. Combined with position data, every point gets an exact location, building a live 3D map.

Where it's used

• Mapping and surveying: agencies like NOAA and the US Geological Survey fly lidar to map coastlines, forests and terrain, spotting landslides and faults hidden under trees.
• Self-driving cars: robotaxis from Waymo carry lidar around the vehicle to see in 3D, day or night.
• Robots: warehouse and factory robots, including autonomous mobile robots, use it to map spaces and avoid obstacles.
• Phones: iPhone Pro models include a small lidar scanner that helps with photos in low light.

Lidar vs. cameras vs. radar

Each sensor has strengths. Waymo combines all three: cameras read traffic lights and signs, radar measures speed and works in bad weather, and lidar measures distance directly in precise 3D.

Tesla is the notable exception. It dropped radar and relies on cameras alone, betting that AI can judge distance the way human eyes do. Whether cameras alone are enough for full self-driving is one of the biggest open debates in the industry.