Lidar

A sensor that fires laser pulses and times their reflections to build a precise 3D map of its surroundings.

• Distance comes from time of flight: light travels about 30 cm per nanosecond, so timing precision sets range accuracy.
• Automotive units return millions of points per second, measuring shape directly, even at night, where cameras must infer it.
• Prices fell from about $75,000 for early spinning units to a few hundred dollars for some automotive sensors today.
• Rain, fog and snow scatter the beam; Tesla relies on cameras alone, while Waymo and most others fuse lidar, cameras and radar.