ADS-B (Automatic Dependent Surveillance–Broadcast)
Also known as: Automatic Dependent Surveillance – Broadcast
ADS-B, or Automatic Dependent Surveillance–Broadcast, is a surveillance technology in which an aircraft determines its own position — usually from GNSS — and periodically broadcasts it, along with identity and other data, so that air traffic control and other aircraft can receive it. It supports surveillance without relying solely on ground radar and is the basis of much publicly available flight tracking.
Reviewed by AeroVigil GNSS Monitoring Desk · 2026-05-31
An ADS-B Out system broadcasts the aircraft's position, altitude, velocity and identification at regular intervals. Ground stations and suitably equipped aircraft receive these broadcasts, giving controllers a real-time picture in areas with little or no radar coverage and enabling traffic awareness between aircraft. Because the position is derived by the aircraft itself rather than measured by a ground sensor, ADS-B is described as dependent surveillance.
ADS-B has become widely mandated and is the source of much open flight-tracking data, since its broadcasts are unencrypted and can be received by anyone with an appropriate receiver. This openness aids transparency and safety but also means aircraft movements are publicly observable. Its dependence on GNSS also links ADS-B to navigation integrity: GNSS jamming or spoofing can degrade or falsify the position an aircraft broadcasts.
Publicly visible ADS-B data is one of the open-source inputs used to understand air activity, including in and around contested regions. AeroVigil treats such flight data as one open-source signal among several, corroborated against official information rather than relied on alone.
Frequently asked
- What is the difference between ADS-B and radar?
- Radar measures an aircraft's position from the ground by reflecting or interrogating signals. ADS-B has the aircraft determine its own position, typically from GNSS, and broadcast it. ADS-B therefore provides surveillance where radar coverage is limited, but it depends on the accuracy of the aircraft's own navigation.
- Why can anyone track aircraft using ADS-B?
- ADS-B broadcasts are unencrypted and transmitted openly, so they can be received by any suitable antenna. This is what allows public flight-tracking services to display live aircraft positions.
Related terms
Sources
- ICAO Annex 10 — Aeronautical Telecommunications
- ICAO Doc 9871 — Technical Provisions for Mode S Services and Extended Squitter