Aircraft positions picked up by ESA's Proba-V minisatellite, using an experimental Automatic Dependent Surveillance – Broadcast (ADS-B) receiver. These signals are regularly broadcast from aircraft, giving flight information such as speed, position and altitude. All aircraft entering European airspace are envisaged to carry ADS-B in the coming years.
Proba-V has picked up upwards of 25 million positions from more than 15 000 separate aircraft. The DLR German Aerospace Center and SES team has identified more than 22 000 unique callsigns, identifying more than 15 000 aircraft by their unique International Civil Aviation Organisation (ICAO) addresses (one aircraft can share a callsign with others, depending on the flight route).