What technology is used for real-time tracking of balloons carrying amateur radio transmitters?

Explanation

A balloon payload carries a GPS receiver and a small transmitter that beacons its position as APRS packets; digipeaters and internet gateways forward them, so the flight can be watched on a map in real time. FT8 carries no position data, PACTOR is a point-to-point data mode, and there is no LORAN tracking of this kind.