Definition
Ground-based radar systems operated by Air Traffic Control to detect, identify, and track aircraft in flight, providing controllers with the position, altitude, and identity of aircraft so they can issue separation, sequencing, and routing instructions.
Plain English
The radar that controllers on the ground use to see where aircraft are, how high they are, and who they are, so they can give safe instructions to pilots.
Context Anchor
You will see this term in arrival, approach, and controller-instruction discussions, especially when ATC is monitoring or guiding aircraft by radar.
Derivation
Radar comes from 'RAdio Detection And Ranging' — a system that uses radio signals to find objects and measure their distance. Adding 'ATC' specifies that this radar is the one operated by Air Traffic Control, as opposed to weather radar, military radar, or onboard aircraft radar.
Why Pilots Care
Controllers depend on it to issue headings and altitudes that keep aircraft safely separated and on the correct arrival path.
Intuition Check
ATC radar does not mean a radar unit in your airplane. It means the radar information used by air traffic control to watch and manage aircraft from the ground.
Example Sentence 1
After checking in with the controller, the pilot heard 'radar contact,' confirming that ATC radar was now tracking the flight.
Example Sentence 2
During the STAR, ATC radar allowed the controller to sequence multiple arrivals without conflict.