Definition
A ground-based radar system used by air traffic controllers to detect and display the position of aircraft and vehicles on the airport movement area, including runways and taxiways. It provides controllers with a continuous, high-resolution picture of surface traffic, particularly useful in low visibility conditions such as night, fog, rain, or snow.
Plain English
A special radar at the airport that lets controllers see exactly where every aircraft and vehicle is on the runways and taxiways, even when they cannot see the surface with their own eyes.
Context Anchor
You may see ASDE mentioned in airport operations, tower control, runway safety, and low-visibility ground movement discussions.
Derivation
The name describes its function plainly: it is the equipment that detects activity on the airport surface. Worth noting that 'surface' here means the movement area on the ground (runways, taxiways, ramps) — not the surface of the Earth in a broader sense.
Why Pilots Care
It helps controllers prevent runway incursions and manage ground traffic safely when visibility is poor.
Grounding Statement
Picture the tower having an electronic view of moving aircraft and vehicles on the airport surface when normal vision is limited.
Intuition Check
Do not read “surface” as the entire airport property. In this context, it means the runways and taxiways where aircraft and vehicles move.
Example Sentence 1
During the heavy fog, the tower controller relied on ASDE to track aircraft taxiing to the runway.
Example Sentence 2
During fog, ASDE gave controllers a clear picture of all surface traffic and reduced the chance of conflicts.