Automatic Dependent Surveillance–Broadcast

Automatic Dependent Surveillance–Broadcast (ADS-B) is an aviation surveillance technology and form of Electronic Conspicuity in which an aircraft (or other airborne vehicles such as drones approved to fit "ADS-B Out") determines its position via satellite navigation or other sensors and periodically broadcasts its position and other related data, enabling it to be tracked. The information can be received by air traffic control ground-based or satellite-based receivers as a replacement for secondary surveillance radar (SSR). Unlike SSR, ADS-B does not require an interrogation signal from the ground or from other aircraft to activate its transmissions. ADS-B can also receive point-to-point by other nearby equipped "ADS-B In" equipped aircraft (or drones) to provide traffic situational awareness and support self-separation. ADS-B is "automatic" in that it requires no pilot or external input to trigger its transmissions. It is "dependent" in that it depends on data from the aircraft's navigation system to provide the transmitted data.

ADS-B is a key part of ICAO's approved aviation surveillance technologies and is being progressively incorporated into national airspaces worldwide. For example, it is an element of the United States Next Generation Air Transportation System (NextGen), the Single European Sky ATM Research project (SESAR), and India’s Aviation System Block Upgrade (ASBU). ADS-B equipment is mandatory for instrument flight rules (IFR) category aircraft in Australian airspace; the United States has required many aircraft (including all commercial passenger carriers and aircraft flying in areas that required a SSR transponder) to be so equipped since January 2020; and, the equipment has been mandatory for some aircraft in Europe since 2017. Canada uses ADS-B for surveillance in remote regions not covered by traditional radar (areas around Hudson Bay, the Labrador Sea, Davis Strait, Baffin Bay and southern Greenland) since January 15, 2009. Aircraft operators are encouraged to install ADS-B products that are interoperable with US and European standards, and Canadian air traffic controllers can provide better and more fuel-efficient flight routes when operators can be tracked via ADS-B.