Automatic Dependent Surveillance-Broadcast (ADS-B) is a radio communications system used by aircraft worldwide to transmit position and identification information. It uses a frequency of 1090 MHz, sending data using a modulation scheme called Pulse Position Modulation (PPM). To monitor this system you could purchase a dedicated ADS-B receiver for several hundred dollars, or design your own in software for an SDR platform. But if you own a RTL-SDR dongle, you already have all the hardware you need and we’ve found some free programs which will get you monitoring ADS-B in minutes.
ADSB# is an open source project from the crew at SDR#. It allows you to access your RTL-SDR dongle with prearranged parameters to receive raw data traffic from aircraft transmitting ADS-B data. The ADSB# code is available in both Windows executable and source.
Once you have ADSB# operational, you’ll need a way to convert its raw hex data output into usable information. Enter ADSBscope. ADSBscope can be downloaded from the developer sprut.de in a zip file containing everything you need for a Windows installation (including Delphi source code.) ADSBscope is an excellent GUI which acts as a client on your computer taking output from the SDR# (server) and presenting it in listing and map format.
You’ll want to read Henry Forte’s excellent 15 page PDF QuickStart Guide for the details on using these outstanding programs.
For more information on ADS-B tech and its security vulnerabilities, see Andrei Costin and Auŕelien Francillon’s interesting paper entitled Ghost in the Air (Traffic). There’s also good information to be found in these materials from Eurocontrol air traffic management training.