Containment is sometimes good. While I was stuck in my London apartment, the health crisis gave me the opportunity to work on various projects that had been shelved for a long time. Over the past three months, I have been able to improve my photo system, build a new meteorological measurement device, take part in wildlife photography in the British capital, but also develop a radio system defined by software to monitor the air traffic in real time.
The objective of this system is to supply location data to air traffic via a growing network of tracking stations using the GPS positions that most planes transmit to build a world map of traffic. This approach, ADS-B, aims to make it easier for aircraft to locate and for air traffic control to follow them. The fact that the data is accessible to all is only a side effect.
It is quite easy to receive ADS-B signals: they are broadcast on a known frequency, 1090 MHz, and must provide data in a determined format. If you have the right receiver, this binary data can be quickly translated into coordinates that can be plotted on a map, using the call signs to find the type and owner of the aircraft. You've probably seen services like Flightradar24 and Flightaware that offer ADS-B information to anyone with a web browser.