Automatic Dependent Surveillance–Broadcast

Automatic Dependent Surveillance–Broadcast (ADS-B) is an aviation surveillance technology and form of electronic conspicuity in which an aircraft 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 ground-based - including air traffic control - or satellite-based receivers as a replacement for secondary surveillance radar (SSR).

Source: Wikipedia — Automatic Dependent Surveillance–Broadcast (CC BY-SA 4.0)