“The universe is a pretty big place. If it’s just us, seems like an awful waste of space.”
― Carl Sagan, Contact

Automatic Dependent Surveillance-Broadcast

Automatic Dependent Surveillance-Broadcast (ADSB) is a surveillance technology in which an aircraft determines its position via satellite navigation and periodically broadcasts it, enabling it to be tracked. … It can also be received by other aircraft to provide situational awareness and allow self separation. And It can be received by RTL-SDR very easily:

The ADS-B system has three main components: 1) ground infrastructure, 2) airborne component, and 3) operating procedures.

  • A transmitting subsystem that includes message generation and transmission functions at the source; e.g., aircraft.
  • The transport protocol; e.g., VHF (VDL mode 2 or 4), 1090ES, or 978 MHz UAT.
  • A receiving subsystem that includes message reception and report assembly functions at the receiving destination; e.g., other aircraft, vehicle or ground system.
  • The source of the state vector and other transmitted information as well as user applications are not considered to be part of the ADS-B system

To set up an ADSB air radar you will need four things.

  1. A working RTL-SDR dongle. The R820T or R820T2 tuner is recommended for best performance at 1090 MHz.
  2. A vertically polarized antenna tuned to 1090 MHz.
  3. Software for listening and decoding ADS-B.
  4. Software to graphically display the received aircraft location data.

There are so many great tutorials on this, I chose not to replicate them here, but rather provide a list of a few good ones:

Below is a live feed from my ADS-B Receiver from my home, using a homemade co-linear coax antenna.  You can view it on your own browser by clicking here VirtualRadar, note that my system has many layers that I have added to show imagery from my Geo stationary Weather Satellite system.
If it is not feeding, I might be doing some work on the system, otherwise, it should run 24/7. It is being fed from a FlightRadar24 Raspberry Pi running FlightRadar24 that I set up.

I then pipe that data from the PI Aware system via TCP into my Virtual Radar System, which then plots and shows the aircraft that my antenna system can pick up. In addition to this, I use Virtual Radar Server to then port to MilRadiocomms.com which is another group that scans and tracks military flights- you can see that data HERE

Best of all, almost all of this software is open source, which usually means free!