Modes_Gui – 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.
cyborg@cyborg:~$ sudo modes_gui