ATC Read More: Radar

Radar

Radar systems at airports use radio waves to detect the position and range of aircraft and to provide information to air traffic controllers using these two systems:

Primary radar: A large rotating antenna sends out a fan-shaped beam of microwaves. When the microwaves hit an aircraft, they reflect back to the antenna. The radar calculates the time it takes for the signal to return, determining the distance to the plane.

Secondary radar: A second rotating antenna interrogates the aircraft’s transponder, which sends back a radio signal with the aircraft’s identification, altitude and emergency status. This information is displayed on the radar screen along with the information gathered by the primary radar.