Automatic Dependent Surveillance–Broadcast
A surveillance technology where aircraft automatically broadcast their GPS-derived position, altitude, speed, and identification on 1090 MHz.
What is ADS-B?
ADS-B (Automatic Dependent Surveillance–Broadcast) is the backbone of modern air traffic surveillance. Each equipped aircraft computes its own position using GPS and broadcasts it on 1090 MHz (ADS-B Out) twice per second. Ground stations, other aircraft, and satellite receivers collect these broadcasts, creating a real-time picture of global air traffic. Platforms like Flightradar24 and ADS-B Exchange rely on this data.
The "Dependent" in ADS-B is critical: the system depends entirely on GPS for position data. When GPS is jammed or spoofed, ADS-B broadcasts become unreliable or cease altogether. This creates both a safety concern and an intelligence opportunity — gaps or anomalies in ADS-B data over a region are strong indicators of GPS interference activity.
ADS-B Out became mandatory in the United States (FAA) in January 2020 and in the European Union (EASA) for most aircraft by June 2020. However, ADS-B signals are unencrypted and unauthenticated, making them vulnerable to spoofing — a concern that has driven research into ADS-B message authentication standards expected to begin deployment by 2027.
Why It Matters for Airspace Risk
ADS-B data is one of the most valuable real-time signals for airspace risk detection. Sudden disappearance of ADS-B tracks over a region suggests GPS jamming. Position jumps or impossible trajectories indicate spoofing. Airlines rerouting around a FIR show up as traffic pattern shifts in ADS-B data before any official NOTAM may be issued. FlySafe analyzes ADS-B patterns to detect emerging airspace disruptions, often identifying GPS interference events within minutes of their onset.
Key Facts
- •ADS-B Out is mandatory for most commercial aircraft in US airspace (since 2020) and EU airspace (since 2020).
- •Aircraft broadcast position updates twice per second on 1090 MHz — unencrypted and receivable by anyone with a $20 antenna.
- •Space-based ADS-B receivers (Aireon constellation on Iridium satellites) provide global coverage, including over oceans.
- •ADS-B anomalies in the Eastern Mediterranean in 2024 were among the first indicators of large-scale GPS spoofing campaigns.
Related Terms
Related Case Studies
This definition is for informational purposes. Always consult official ICAO/EASA/FAA documentation for regulatory definitions.