The Same Data as FlightRadar24
ADS-B (Automatic Dependent Surveillance–Broadcast) transponders broadcast GPS position, altitude, speed, and identity every ~0.5s on 1090MHz. FlightRadar24, Flightaware, and SENTINEL all decode the same raw signal from ~40,000 ground receivers worldwide. OpenSky Network is the open-access nonprofit version. SENTINEL polls every 15 seconds — real callsigns, real positions.