acarsdec is a multi-channels ACARS decoder with built-in rtl_sdr, soapysdr, airspy or sdrplay device support. Since 3.0, it can work with a database backend: acarsserv to store received ACARS messages.
- arbitrary number of channels decoded simultaneously (limited by bandwidth and CPU power)
- error detection AND correction
- input via either audio file (including raw audio), ALSA soundcard, rtl_sdr, SoapySDR, airspy or sdrplay software defined radios (SDR)
- multiple simultaneous outputs via file, UDP or MQTT
- multiple output formats: one line, full text, planeplotter, acarsserv, JSON and live monitoring
- decoding of ARINC-622 ATS applications (ADS-C, CPDLC) via libacars library
- statistics reporting via StatsD-compliant interface
GPLv2-only - http://www.gnu.org/licenses/gpl-2.0.html
Copyright: (C) 2015-2022 Thierry Leconte 2015-2022, (C) 2024 Thibaut VARENE
This program is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License version 2, as published by the Free Software Foundation.
This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
See LICENSE.md for details
acarsdec requires CMake, pkg-config and a C compiler.
It depends on some optional external libraries :
- librtlsdr for RTL-based SDR input (http://sdr.osmocom.org/trac/wiki/rtl-sdr)
- libsoapysdr for SoapySDR input (https://github.com/pothosware/SoapySDR)
- libairspy for airspy SDR input (https://github.com/airspy/airspyone_host)
- libmirsdrapi-rsp for sdrplay software radio input
- libsndfile for audio input (https://github.com/libsndfile/libsndfile)
- libasound for ALSA input (https://github.com/alsa-project/alsa-lib)
- libacars for decoding ATS applications (https://github.com/szpajder/libacars)
- libcjson for JSON output support (https://github.com/DaveGamble/cJSON)
- paho-mqtt3a (and libcjson) for MQTT output support (https://github.com/eclipse/paho.mqtt.c)
mkdir build
cd build
cmake .. -DCMAKE_C_FLAGS="-march=native"
make
All optional libraries will be autodected, a summary of what is enabled will be printed by cmake.
The -DCMAKE_C_FLAGS="-march=native" argument to cmake will produce an acarsdec executable
that is optimized for the machine it was built on (and may not run correctly on other devices).
It can be ommitted for a platform-generic build (with possibly reduced performance).
It seems that the compile option -march=native may be problematic on Raspberry Pi.
In that case, one can use the following cmake parameter instead in the above procedure:
- for PI 2B :
-DCMAKE_C_FLAGS="-mcpu=cortex-a7 -mfpu=neon-vfpv4" - for PI 3B :
-DCMAKE_C_FLAGS="-mcpu=cortex-a53 -mfpu=neon-fp-armv8" - for PI 4B :
-DCMAKE_C_FLAGS="-mcpu=cortex-a72 -mfpu=neon-fp-armv8"
sudo make install
acarsdec operation can be controlled via multiple command line parameters (the availability of which depends on which optional libraries have been enabled at build time), they are detailed below:
-i <stationid> station id used in statsd reports and network destinations (default: hostname)
-A don't output uplink messages (ie : only aircraft messages)
-e don't output empty messages (ie : _d,Q0, etc ...)
-b <filter> filter output by label (ex: -b "H1:Q0" : only output messages with label H1 or Q0)
-t <seconds> set forget time (TTL) in seconds for monitor mode (default: 600)
--statsd host=HOST,port=1234 enable statsd reporting to host "HOST" (name or IP) on port "1234"
--output FORMAT:DESTINATION:DESTPARAMS (see below for supported output formats and destinations. DESTPARAMS are coma-separated: ',')
If libacars is enabled, the following extra option is available:
--skip-reassembly disable reassembling fragmented ACARS messages
Multiple instances of --output can be used. At least one is required.
See --output help for a list of supported formats and destinations.
Not all combinations of formats and destinations are valid, acarsdec will complain if an invalid combination is chosen.
One (and only one) input source must also be selected, see below. Options (including frequencies) can be provided in any order.
onelinefor single line text decodingfullfor full text decodingmonitorfor live decodingppfor PlanePlotternativefor Acarsdec native format
With CJSON support enabled:
jsonfor JSON outputroutejsonfor flight route output in JSON format
Outputs to a file (including stdout, the default). Supports all output formats.
DESTPARAMS are optional (no param implies output to stdout) and can be:
path=followed by either-for stdout or a path to a logfilerotate=followed by one ofnone,hourlyordailyto dis/enable hourly/daily logfile rotation
Outputs to IPv4 or IPv6 network via UDP. Supports all but monitor output formats.
DESTPARAMS are:
host=(required) followed by a hostname or an IP addressport=(optional) followed by a port number (defaults to 5555)
With PAHO MQTT support enabled, pushes JSON to remote MQTT server. Supports only json and routejson output formats.
DESTPARAMS are:
uri=(required) followed by a valid MQTT URI (e.g.tcp://host:port). Can be repeated up to 15 times.user=(optional) followed by a usernamepasswd=(optional) followed by a passwordtopic=(optional) followed by a topic (defaults toacarsdec/<stationid>)
--rtlsdr <device> decode from rtl dongle number <device> or S/N <device>
-g <gain> set rtl gain in db (0 to 49.6; >52 and -10 will result in AGC; default is AGC)
-p <ppm> set rtl ppm frequency correction (default: 0)
-m <rateMult> set rtl sample rate multiplier: 160 for 2 MS/s or 192 for 2.4 MS/s (default: 160)
-B <bias> enable (1) or disable (0) the bias tee (default is 0)
-c <freq> set center frequency to tune to in MHz, e.g. 131.800 (default: automatic)
--airspy <device> decode from airspy dongle number <device> or hex serial <device>
-g <linearity_gain> set linearity gain [0-21] (default: 18)
Note: acarsdec will try to set the R820T tuner bandwidth to suit given frequencies. See https://tleconte.github.io/R820T/r820IF.html
--sdrplay decode from sdrplay
-L <lnaState> set the lnaState (depends on the device)
-G <GRdB> gain reduction in dB's, range 20 .. 59 (default: -100 is autogain)
-c <freq> set center frequency to tune to in MHz, e.g. 131.800 (default: automatic)
--soapysdr <params> decode from a SoapySDR designed by device_string <params>\n"
-g <gain> set gain in db (-10 will result in AGC; default is AGC)\n"
-p <ppm> set ppm frequency correction (default: 0)\n"
-c <freq> set center frequency to tune to in MHz, e.g. 131.800 (default: automatic)\n"
-m <rateMult> set sample rate multiplier: 160 for 2 MS/s or 192 for 2.4 MS/s (default: 160)\n"
-a <antenna> set antenna port to use (default: soapy default)\n");
All SDR sources described above expect a list of frequencies <f1> [<f2> [...]] to decode from, expressed in decimal MHz
e.g. 131.525 131.725 131.825.
All formats supported by libsndfile can be processed.
--sndfile <file> decode from <file>, which must be a libsndfile supported format and sampled at a multiple of 12.5kHz
To decode raw audio, extra parameters must be provided. Example:
--sndfile <file>,subtype=<N> decode single-channel raw in libsndfile-supported <N> subtype from <file> sampled at 12.5KHz.
For raw audio, the sample rate multiplier can be adjusted using -m. See --sndfile help for more details.
libsndfile-supported subtypes are listed here: http://libsndfile.github.io/libsndfile/api.html#open
NB: <file> can be /dev/stdin to process piped-in data.
--alsa <alsadevice> decode from ALSA PCM device <alsadevice>
Decoding from rtl dongle number 0 on 3 frequencies, sending aircraft messages in native format to 192.168.1.1 on port 5555 and no other loging :
acarsdec -A --output native:udp:host=192.168.1.1,port=5555 --rtlsdr 0 131.525 131.725 131.825
Monitoring from rtl dongle with serial number ACARS2 on 1 frequency with gain 34.0 :
acarsdec --output monitor:file -g 34 --rtlsdr ACARS2 130.450
Logging to file "airspy.log" rotated daily, from airspy mini with serial number 0xa74068c82f531693 on 11 frequencies with gain 18 :
acarsdec --output full:file:path=airspy.log,rotate=daily -g 18 --airspy 0xa74068c82f531693 129.350 130.025 130.425 130.450 130.650 131.125 131.475 131.550 131.600 131.725 131.850
Decoding with JSON output to stdout, an sdrplay device using Soapy driver, and specifying Antenna C :
acarsdec --output json:file:path=- --soapysdr driver=sdrplay,agc_setpoint=-15 -a "Antenna C" 130.025 130.450 130.825 131.125 131.550 131.650 131.725
Decoding 7 channels from rtl dongle with serial '86000034', filtering empty messages, setting ppm correction to 36, gain to 48 dB, full text to stdout, sending JSON to feed.acars.io:5550 with station ID "MY-STATION-ID", sending statsd data to host "statsd.lan" port "8125":
acarsdec -e -i MY-STATION-ID --output full:file --output json:udp:host=feed.acars.io,port=5550 -p 36 --rtlsdr 86000034 -g 48 131.550 130.825 130.850 131.525 131.725 131.825 131.850 --statsd host=statsd.lan,port=8125
Decoding raw CPU-endian single-channel PCM16 from stdin, providing one line per message on stdout:
acarsdec --sndfile file=/dev/stdin,subtype=0x02 --output oneline:file
#2 (L: -5 E:0) 25/12/2016 16:26:40 .EC-JBA IB3166 X B9 J80A /EGLL.TI2/000EGLLAABB2
#3 (L: 8 E:0) 25/12/2016 16:26:44 .G-OZBF ZB494B 2 Q0 S12A
#3 (L: 0 E:0) 25/12/2016 16:26:44 .F-HZDP XK773C 2 16 M38A LAT N 47.176/LON E 2.943
[#1 (F:131.825 L: 4 E:0) 25/12/2016 16:27:45 --------------------------------
Aircraft reg: .A6-EDY Flight id: EK0205
Mode : 2 Label : SA Id : 4 Ack : !
Message no: S31A :
0EV162743VS/
[#3 (F:131.825 L: 3 E:0) 25/12/2016 16:28:08 --------------------------------
Aircraft reg: .F-GSPZ Flight id: AF0940
Mode : 2 Label : B2 Id : 1 Ack : !
Message no: L07A :
/PIKCLYA.OC1/CLA 1627 161225 EGGX CLRNCE 606
AFR940 CLRD TO MUHA VIA ETIKI
RANDOM ROUTE
46N020W 45N027W 44N030W 40N040W 36N050W
34N055W 32N060W 27N070W
FM ETIKI/1720 MNTN F340 M083
ATC/LEVEL CHANGE
END O
Acarsdec monitor
Aircraft Flight Nb Channels Last First
.CN-RNV AT852X 9 .x. 16:25:58 16:21:05
.F-HBMI ZI0321 1 .x. 16:25:52 16:25:52
.F-GSPZ AF0940 6 ..x 16:25:21 16:22:30
.D-ABUF DE0252 1 .x. 16:25:20 16:25:20
{"timestamp":1516206744.1849549,"channel":2,"freq":130.025,"level":-22,"error":0,"mode":"2","label":"H1","block_id":"6","ack":false,"tail":".N842UA","flight":"UA1412","msgno":"D04G","text":"#DFB9102,0043,188/9S101,0039,181/S0101,0043,188/0S100,0039,182/T1100,0043,188/1T099,0039,182/T2099,0043,189/2T098,0039,182/T3098,0043,189/3T097,0039,182/T4098,0043,189/4T097,0039,183/T5098,0043,189/5T097,0039,1","end":true,"station_id":"sigint"}
{"timestamp":1516206745.249615,"channel":2,"freq":130.025,"level":-24,"error":2,"mode":"2","label":"RA","block_id":"R","ack":false,"tail":".N842UA","flight":"","msgno":"","text":"QUHDQWDUA?1HOWGOZIT\r\n ** PART 01 OF 01 **\r\nHOWGOZIT 1412-17 SJC\r\nCI: 17 RLS: 01 \r\nSJC 1615/1625 171A\r\nBMRNG 1630 37 159-\r\nTIPRE 1638 37 145\r\nINSLO 1701 37 125\r\nGAROT 1726 37 106\r\nEKR 1800 ","end":true,"station_id":"sigint"}
{"timestamp":1543677178.9600339,"flight":"BA750P","depa":"EGLL","dsta":"LFSB"}
[#2 (F:131.725 L:-33 E:0) 30/11/2018 19:45:46.645 --------------------------------
Mode : 2 Label : H1 Id : 3 Nak
Aircraft reg: G-OOBE Flight id: BY01WH
No: F57A
#M1B/B6 LPAFAYA.ADS.G-OOBE0720BD17DFD188CAEAE01F0C50F3715C88200D2344EFF62F08CA8883238E3FF7748768C00E0C88D9FFFC0F08A9847FFCFC16
ADS-C message:
Basic report:
Lat: 46.0385513
Lon: -5.6569290
Alt: 36012 ft
Time: 2744.000 sec past hour (:45:44.000)
Position accuracy: <0.05 nm
NAV unit redundancy: OK
TCAS: OK
Flight ID data:
Flight ID: TOM1WH
Predicted route:
Next waypoint:
Lat: 49.5972633
Lon: -1.7255402
Alt: 36008 ft
ETA: 2179 sec
Next+1 waypoint:
Lat: 49.9999809
Lon: -1.5020370
Alt: 30348 ft
Earth reference data:
True track: 35.2 deg
Ground speed: 435.5 kt
Vertical speed: -16 ft/min
Air reference data:
True heading: 24.3 deg
Mach speed: 0.7765
Vertical speed: -16 ft/min