acarsdec_int Files

Acarsdec_int is a light version  of Thierry Leconte's acarsdec. It is a multi-channels acars decoder with built-in rtl_sdr front end.
Current version is based on acarsdec v 3.2 and has all the same core ACARS traffic decoding. Some DSP functions are modified to reduce load on low end CPUs such as ARMv5 or Raspberry Pi
It may come useful on old weak Intel machines too
CPU load is reduced dramatically from 90%+ to about 40% on ARM5 makeing it possible to decode 4 simultaneous channels on a board as weak as for example PogoPlug Mobile ( 800MHz ARM5 without FPU)


Features :

 - up to four channels decoded simultaneously
 - error detection AND correction
 - input  via a rtl dongle (http://sdr.osmocom.org/trac/wiki/rtl-sdr) 
 - could send packet over UDP in planeplotter format or in its own format to acarsserv to store ina sqlite database.

The multi channels decoding is particularly useful with the rtl dongle. It allows to directly listen simultaneously to 4 different frequencies , with a very low cost hardware.

Usage: acarsdec  [-v] [-o lv] [-A] [-n|N ipaddr:port] [i- stationid] [-l logfile]  -a alsapcmdevice  |   -r rtldevicenumber  f1 [f2] [f....] | -s f1 [f2] [f....]

 -v :			verbose
 -A :			don't display uplink messages (ie : only aircraft messages)
 -o lv :		output format : 0: no log, 1 one line by msg., 2 full (default) 
 -l logfile :		Append log messages to logfile (Default : stdout).

 -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
 -i station id:		id use in acarsdec network format.

 -a alsapcmdevice :	decode from soundcard input alsapcmdevice (ie: hw:0,0)

 -r rtldevice f1 [f2] [f...] :		decode from rtl dongle number or S/N "rtldevice" receiving at VHF frequencies "f1" and optionaly "f2" to "f4" in Mhz (ie : -r 0 131.525 131.725 131.825 ). Frequencies must be in the same two Megahertz.
 -g gain :		set rtl preamp gain in tenth of db (ie -g 90 for +9db). By default use maximum gain
 -p ppm :		set rtl ppm frequency correction

 -s f1 [f2] [f...] :		decode from airspy receiving at VHF frequencies "f1" and optionaly "f2" to "f4" in Mhz (ie : -s  131.525 131.725 131.825 ). Frequencies must be in the same two Megahertz.


Examples :


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