Acarsdec is a multi-channels acars decoder with built-in rtl_sdr, airspy front end or sdrplay device. Since 3.0, It comes with a database backend : acarsserv to store received acars messages. (See acarsserv chapter below).
- up to 8 channels decoded simultaneously
- error detection AND correction
- input via rtl_sdr, or airspy or sdrplay software defined radios (SDR)
- logging data over UDP in planeplotter or acarsserv formats to store in an sqlite database, or JSON for custom processing.
- decoding of ARINC-622 ATS applications (ADS-C, CPDLC) via libacars library
Multi-channel decoding is particularly useful with broadband devices such as the RTLSDR dongle, the AIRspy and the SDRplay device. It allows the user to directly monitor to up to 8 different frequencies simultaneously with very low cost hardware.
For RTL-SDR:
acarsdec [-o lv] [-t time] [-A] [-b filter ] [-e] [-n|N|j ipaddr:port] [-i stationid] [-l logfile [-H|-D]] -r rtldevicenumber f1 [f2] [... fN] | -s f1 [f2] [... fN]
For Airspy R2 / Mini:
acarsdec [-o lv] [-t time] [-A] [-b filter ] [-e] [-n|N|j ipaddr:port] [-i stationid] [-l logfile [-H|-D]] [-g gain] -s airspydevicenumber f1 [f2] [... fN] | -s f1 [f2] [... fN]
-o lv : output format : 0 : no log, 1 : one line by msg, 2 : full (default), 3 : monitor mode, 4 : msg JSON, 5 : route JSON
-t time : set forget time (TTL) in seconds in monitor mode(default=600s)
-A : don't display uplink messages (ie : only aircraft messages)
-e : don't output empty messages (ie : _d,Q0, etc ...)
-l logfile : append log messages to logfile (Default : stdout)
-H : rotate log file once every hour
-D : rotate log file once every day
-n ipaddr:port : send acars messages to addr:port via UDP in planeplotter compatible format
-N ipaddr:port : send acars messages to addr:port via UDP in acarsdec format
-j ipaddr:port : send acars messages to addr:port via UDP in JSON format
-i station id: id use in acarsdec network format.
-b filter: filter output by label (ex: -b "H1:Q0" : only output messages with label H1 or Q0"
for the RTLSDR device
-r rtldevice f1 [f2] ... [fN] : decode from rtl dongle number or S/N "rtldevice" receiving at VHF frequencies "f1" and optionally "f2" to "fN" in Mhz (ie : -r 0 131.525 131.725 131.825 ). Frequencies must be within the same 2MHz.
-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
-B bias : Enable (1) or Disable (0) the bias tee (default is 0)
for the AirSpy device -g gain : set airspy gain (0..21)
-s airspydevice f1 [f2] ... [fN] : decode from airspy device number or S/N "airspydevice" receiving at VHF frequencies "f1" and optionally "f2" to "fN" in Mhz (ie : -s 131.525 131.725 131.825 ). Frequencies must be within the same 2MHz.
for the SDRplay device
-s f1 [f2] ... [fN] : decode from SDRplay receiving at VHF frequencies "f1" and optionally "f2" to "fN" in Mhz (ie : -s 131.525 131.725 131.825 ). Frequencies must be within the same 2MHz.
-L lnaState: set the lnaState (depends on the selected SDRPlay hardware)
-G GRdB: set the Gain Reduction in dB's. -100 is used for agc.
for the SoapySDR device
-d devicestring f1 [f2] ... [fN] : decode from a SoapySDR device at VHF frequencies f1 and optionally f2 to fN in Mhz (ie : -d driver=rtltcp 131.525 131.725 131.825 ).
-g gain : set gain in db (-10 will result in AGC; default is AGC)
-p ppm : set rtl ppm frequency correction
-c freq : set center frequency to tune to
-m rateMult : set sample rate multiplier: 160 for 2 MS/s or 192 for 2.4 MS/s (default: 160)
Decoding from rtl dongle number 0 on 3 frequencies , sending aircraft messages only to 192.168.1.1 on port 5555 and no other loging :
acarsdec -A -N 192.168.1.1:5555 -o0 -r 0 131.525 131.725 131.825
Decoding from airspy on 3 frequencies with verbose logging :
acarsdec -s 131.525 131.725 131.825
#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
acarsdec must compile directly on any modern Linux distrib.
It needs cmake and a C compiler.
It depends on some external libraries :
- libusb
- librtlsdr for software radio rtl dongle input (http://sdr.osmocom.org/trac/wiki/rtl-sdr)
- libairspy for airspy software radio input
- libmirsdrapi-rsp for sdrplay software radio input
- optionaly libacars for decoding ATS applications (https://github.com/szpajder/libacars)
⚠️ Raspberry Pi users : read Troubleshooting first
For rtl_sdr :
mkdir build
cd build
cmake .. -Drtl=ON
make
sudo make install
For airspy :
mkdir build
cd build
cmake .. -Dairspy=ON
make
sudo make install
For sdrplay :
mkdir build
cd build
cmake .. -Dsdrplay=ON
make
sudo make install
Notes :
- Airspy version will set the R820T tuner bandwidth to suit given frequencies. See : (https://tleconte.github.io/R820T/r820IF.html)
- libacars support is optional. If the library (version 2.0.0 or later) is installed and can be located with pkg-config, it will be enabled.
- If you have call cmake .. -Dxxx one time, the option will be sticky . Remove build dir and redo to change sdr option.
It seems that the default compile options -march=native is problematic on Raspberry Pi.
In CMakeLists.txt change the line :
add_compile_options(-Ofast -march=native)
to :
for PI 2B : add_compile_options(-Ofast -mcpu=cortex-a7 -mfpu=neon-vfpv4)
for PI 3B : add_compile_options(-Ofast -mcpu=cortex-a53 -mfpu=neon-fp-armv8)
for PI 4B : add_compile_options(-Ofast -mcpu=cortex-a72 -mfpu=neon-fp-armv8)
then rebuild (remove anyting in build directory then follow Compilation procedure)
acarsserv is a companion program for acarsdec. It listens to acars messages on UDP coming from one or more acarsdec processes and stores them in a sqlite database.
See : acarsserv
acarsdec and acarsserv are Copyright Thierry Leconte 2015-2018
These code are free software; you can redistribute it and/or modify it under the terms of the GNU Library General Public License version 2 published by the Free Software Foundation.
They include cJSON Copyright (c) 2009-2017 Dave Gamble and cJSON contributors