"Automatic Dependent Surveillance - Broadcast" is an aircraft navigation radio that transmits using the 978 MHz frequency for air traffic control and such. The transmission contains location data for the aircraft. It's the same frequency the signal "from Proxima Centauri" used.

https://www.faa.gov/nextgen/programs/adsb/

Or maybe it's a Vogon Constructor Fleet out of Proxima Centauri and it's headed our way...