Definition
A surveillance technology in which an aircraft automatically transmits its own position, altitude, velocity, and identification — derived from onboard navigation sources such as GPS — at regular intervals on a defined frequency. Air traffic control and other suitably equipped aircraft receive this broadcast directly, without needing to interrogate the aircraft with radar. The system is 'automatic' because it operates without pilot or controller input, 'dependent' because it relies on the aircraft's own navigation equipment for the position data, 'surveillance' because it provides traffic information for control and separation, and 'broadcast' because the data is transmitted openly to any receiver in range.
Plain English
Your aircraft figures out where it is using GPS and constantly tells everyone — controllers and other planes — over the radio. They don't have to find you with radar; you're already telling them.
Context Anchor
You will see ADS-B in equipment requirements, traffic display discussions, airspace entry rules, and air traffic control surveillance procedures.
Derivation
Each word in the name describes how the system works. 'Automatic' — runs on its own with no pilot action. 'Dependent' — depends on the aircraft's own navigation equipment (mainly GPS) for the position it sends out. 'Surveillance' — used by ATC to watch and separate traffic. 'Broadcast' — sent out openly to anyone listening, not aimed at a specific receiver. Reading the name as a sentence makes the technology easier to remember.
Why Pilots Care
Provides real-time traffic awareness, supports more efficient routing, and meets regulatory requirements for operations in many controlled airspace areas.
Analogy
ADS-B is like a moving name tag that keeps updating your location. Instead of someone asking where you are every few seconds, your aircraft keeps sending that information out for approved receivers to use.
Intuition Check
“Dependent” does not mean the system is optional or weak; it means the position report depends on the aircraft’s own navigation source. “Broadcast” does not mean a voice transmission; it means electronic data sent out for receivers to pick up.
Example Sentence 1
Before flying into the Class B airspace, the pilot confirmed that the aircraft's ADS-B Out was transmitting correctly.
Example Sentence 2
Controllers received precise ADS-B position reports that allowed them to issue accurate traffic advisories.