ADS-B ( Automatic Dependant Surveillance Broadcast ) provides much needed information to pilots and air traffic controllers. ATC can see the location, speed and direction of any aircraft equipped with ADS-B out. Pilots can see other aircraft with ADS-B out and get updated information such as weather and temporary flight restrictions. Historically getting access to this data required expensive avionics but recently a few low cost solutions have appeared.
With some specialized software European USB TV tuners can pickup the ADS-B signals and thanks to mass production such devices can be purchased for under $20. I purchased a tuner that comes with an external antenna from Amazon.
Using a USB OTG cable I connected the tuner to my tablet.
If you need more detailed directions to get this setup head over to the site that made this possible: http://hiz.ch/index.php/home/adsb-receiver
The FAA has mandated that aircraft flying in nearly all controlled airspace must be equipped with ADS-B out by Jan 1st 2020. I hope this mandate helps drive some competition in the market and bring down prices of ADS-B out transponders. In the meantime at least I can pickup ADS-B in with little investment.