Aircraft surveillance
What Is ADS-B?
ADS-B stands for Automatic Dependent Surveillance–Broadcast. It is a surveillance technology that lets equipped aircraft broadcast information that can include position, altitude, ground speed, and identification.
By TransitSatellite · Reviewed October 20, 2026
Automatic, dependent, surveillance, broadcast
Automatic means the system transmits without repeated pilot requests. Dependent refers to its reliance on a position source such as GPS. Surveillance describes its role in determining aircraft position and identity. Broadcast means the information is transmitted for suitable receivers to receive.
ADS-B Out
ADS-B Out is the transmitting side. The FAA says it broadcasts an aircraft’s GPS location, altitude, ground speed, and other data to ground stations and other aircraft about once per second.
ADS-B In
ADS-B In is the receiving side available to appropriately equipped operators. It can provide traffic and other information to cockpit systems. ADS-B In and ADS-B Out serve different roles and should not be treated as interchangeable.
Common questions
Is ADS-B the same as radar?
No. ADS-B uses aircraft broadcasts based on onboard positioning, while radar determines aircraft location using ground-based radio systems.
Does every aircraft appear on public ADS-B websites?
No. Equipment, receiver coverage, provider policies, filtering, privacy measures, and data availability can all affect what a public service displays.
Sources
Flight tracker search
Start with a flight number or route and open the current tracking source.
Search flightsTransportation globe
See the airport layer on the existing TransitSatellite 3D globe.
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