Automatic Packet Reporting System
Automatic Packet Reporting System (APRS) is an amateur radio-based system for real time digital communications of information of immediate value in the local area. Data can include object Global Positioning System (GPS) coordinates, non-directional beacon, weather station telemetry, text messages, announcements, queries, and other telemetry.
Source: Wikipedia — Automatic Packet Reporting System (CC BY-SA 4.0)