radar science definition

1. A method of detecting distant objects and determining their position, speed, material composition, or other characteristics by causing radio waves to be reflected from them and analyzing the reflected waves. The waves can be converted into images, as for use on weather maps.
2. The equipment used in such detecting. See also Doppler effect, lidar, sonar.

radar

A radio antenna sends out a stream of radio waves (light gray). When they reach the airplane, they bounce off of it and send reflected waves (dark gray) back to a receiver in the antenna. The reflected waves are then processed electronically and analyzed to determine the airplane's distance, speed, and position. An image of the airplane is sometimes also generated.