APRS (Automatic Packet Reporting System) is a digital ham radio protocol that broadcasts live position, telemetry, weather and short messages over VHF — and worldwide via the APRS-IS gateway network. Licensed amateur-radio operators have used APRS since the early 1990s as a real-time situational awareness tool.
Once a station beacons a position, every digipeater within RF range repeats it; one of those digipeaters typically forwards it to APRS-IS, the global internet backbone for APRS. APRS World subscribes to that backbone, so the moment a beacon hits the network it lands on the live map.