Definition
A surveillance technology in which an aircraft determines its own position using satellite navigation (GPS) and automatically broadcasts that position, along with altitude, velocity, and identification, at regular intervals over a digital radio link. Air traffic control and other suitably equipped aircraft receive these broadcasts directly, without needing to interrogate the aircraft with radar.
Plain English
The aircraft figures out where it is using GPS and continuously transmits that information out to controllers and other aircraft, so everyone nearby can see exactly where it is.
Context Anchor
You will see ADS-B in discussions of aircraft equipment, traffic displays, controlled airspace requirements, and air traffic control surveillance.
Derivation
Each word describes how it works: 'Automatic' — it transmits on its own without pilot action. 'Dependent' — it depends on an outside source (GPS) to know its position. 'Surveillance' — it is used to keep track of aircraft. 'Broadcast' — the information is sent out openly to anyone listening, rather than to one specific receiver.
Why Pilots Care
It provides more accurate and frequent position data than traditional radar, improving separation and traffic awareness.
Grounding Statement
ADS-B is like the aircraft continually announcing its own position to the aviation system around it.
Intuition Check
Do not read dependent as meaning the aircraft depends on air traffic control for its position. Here, dependent means the system depends on the aircraft’s own position source before it broadcasts the information.
Example Sentence 1
Before flying into Class B airspace, the pilot confirmed the aircraft was equipped with ADS–B Out.
Example Sentence 2
Controllers relied on ADS–B data to maintain safe spacing between arriving aircraft.