NAME

       modes_gui: - Gnuradio Mode-S/ADS-B receiver

DESCRIPTION

       A  Qt  Graphical  User  Interface  to display positions and status messages of aircraft as
       reported on 1090 MHz.

       gr-air-modes implements a software-defined radio receiver for Mode S transponder  signals,
       including ADS-B reports from equipped aircraft.

       Mode  S is the transponder protocol used in modern commercial aircraft.  A Mode S-equipped
       aircraft replies to radar interrogation by either ground radar (secondary surveillance) or
       other  aircraft  ("Traffic  Collision  Avoidance  System",  or  TCAS).  The protocol is an
       extended version of the Mode A/C protocol used in transponders since the  1940s.   Mode  S
       reports  include  a  unique  airframe  identifier  (referred  to as the "ICAO number") and
       altitude (to facilitate  separation  control).   This  receiver  listens  to  the  1090MHz
       downlink  channel;  interrogation  requests at 1030MHz are not received or decoded by this
       program.

       Automatic Dependent Surveillance-Broadcast (ADS-B) is a communication protocol  using  the
       Extended   Squitter   capability   of   the  Mode  S  transport  layer.  There  are  other
       implementations (VDL Mode 2 and UAT, for instance) but Mode S remains  the  primary  ADS-B
       transport for commercial use. The protocol is:

       * Automatic: it requires no pilot input

       * Dependent: it is dependent on altimeter, GPS, and other aircraft
         instrumentation for information

       * Surveillance: it provides current information about the transmitting
         aircraft

       * Broadcast: it is one-way, broadcast to all receivers within range.

       ADS-B-equipped  aircraft  broadcast  ("squitter") their position, velocity, flight number,
       and other interesting information to any receiver within range of the  aircraft.  Position
       reports  are  typically  generated  once  per second and flight indentification every five
       seconds.

       Implementation of ADS-B is mandatory in European airspace as well as in  Australia.  North
       American  implementation is still voluntary, with a mandate arriving in 2020 via the FAA's
       "NextGen" program.

REQUIRES

       An X display, as all user settings as well as displayed data are handled withing the GUI.

       A GNU Radio supported receiver for RF capable of 2 Mbits/second sample rate and tuning  to
       1090 MHz. (Or captured data file or network connection to a data source.)

SEE ALSO

       The command-line application modes_rx

       modes_rx(1)