1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
|
.TH MODES_GUI: "1" "October 2013" "modes_gui" "User Commands"
.SH NAME
modes_gui: \- Gnuradio Mode-S/ADS-B receiver
.SH DESCRIPTION
A Qt Graphical User Interface to display positions
and status messages of aircraft as reported on
1090 MHz.
.LP
gr-air-modes implements a software-defined radio receiver for Mode S
transponder signals, including ADS-B reports from equipped aircraft.
.LP
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.
.LP
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:
.LP
* Automatic: it requires no pilot input
.LP
* Dependent: it is dependent on altimeter, GPS, and other aircraft
instrumentation for information
.LP
* Surveillance: it provides current information about the transmitting
aircraft
.LP
* Broadcast: it is one-way, broadcast to all receivers within range.
.LP
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.
.LP
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.
.SH REQUIRES
An X display, as all user settings as well as displayed data are
handled withing the GUI.
.LP
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.)
.SH "SEE ALSO"
The command-line application
.B modes_rx
.LP
modes_rx(1)
|
