Here is more about ADS-B (Automatic Dependent Surveillance–Broadcast), now installed on most large aircraft in the developed world and increasingly mandated for flight in controlled airspace. It not only provides information to controllers (and anybody else who wants to set up a receiver) on the ground, but also provides pilots situational awareness of other ADS-B equipped aircraft in their vicinity without any reliance upon ground infrastructure.
The hardware and software that Scott Manley used to set up his own ADS-B ground station is the 1090MHz PiAware ADS-B Kit from the FlightAware Store. Here are instructions for installing a station. The software that runs on the Raspberry Pi Zero is PiAware, available from GitHub, which uses Dump1090, also on GitHub, to decode the ADS-B data stream.