ADS-B Explained

Automatic Dependent Surveillance–Broadcast changes the surveillance model from “ground radar measures where the aircraft is” to “the aircraft calculates where it is and broadcasts that information.” Ground stations, other aircraft and even satellites can receive the messages.

“Automatic” means no interrogation is required

The transmitter sends information repeatedly without a controller or radar station requesting each update. That allows frequent position reports.

“Dependent” refers to onboard navigation

The broadcast depends on the aircraft’s own navigation source, typically satellite-based. If that source loses the required integrity, the surveillance data may no longer meet operational standards.

“Surveillance” describes the operational purpose

Controllers use ADS-B to see and separate traffic in approved airspace, often with accuracy and update rates that compare favorably with traditional radar.

“Broadcast” makes reception widely possible

Signals are transmitted openly, which is why hobbyist receiver networks can feed public flight-tracking websites. The technology was designed for aviation surveillance, not for consumer apps.

ADS-B In can provide traffic and weather information

Some aircraft receive broadcasts from other aircraft or ground services, giving pilots a cockpit picture of nearby traffic and, in certain regions, weather products.

Equipage rules depend on airspace and jurisdiction

Many controlled airspace systems require approved ADS-B Out equipment, but mandates and technical standards vary. Pilots must meet the rules for the region and altitude in which they operate.

More aviation guides

Explore more aircraft, pilot, airport and aviation guides on SY.com.

Explore aviation