Automatic dependent surveillance—broadcast (ADS–B) is a surveillance technology in which an aircraft determines its position via satellite navigation and periodically broadcasts it, enabling it to be tracked. The information can be received by air traffic control ground stations as a replacement for secondary surveillance radar, as no interrogation signal is needed from the ground. It can also be received by other aircraft to provide situational awareness and allow self-separation.

    ADS–B is "automatic" in that it requires no pilot or external input. It is "dependent" in that it depends on data from the aircraft's navigation system.

    ADS–B is an element of the United States Next Generation Air Transportation System (NextGen), Airports Authority of India upgrade plans in line with ICAO Global Plan Initiatives and Aviation System Block Upgrade (ASBU) and the Single European Sky ATM Research (SESAR). ADS–B equipment is mandatory for IFR category aircraft in Australian airspace, the United States requires some aircraft to be equipped by 2020 and the equipment will be mandatory for some aircraft in Europe from 2017.Canada is currently using ADS–B for rather limited air traffic control, mainly in the Hudson Bay area.