vdl2monitor service
===================

Monitors 'dumpvdl2' decoder data to support maintaining a VDL2 Ground Stations list.
A text file, originally built for 'MultiPSK' decoder, which holds the translation
of the VDL2 Ground Station address (hexadecimal number) to location information.
'dumpvdl2' decoder program is using this file to log enriched VDL2 GS information.
Since there is no public official VDL2 GS list, this service is a tool to support the
maintenance of a list with data gathered from the collaboration of aviation enthusiasts.

How it works
============
vdl2monitor service forwards 'dumpvdl2' decoder data to 'https://vdl2info.net/' server.
An extra output option is added to 'dumpvdl2' configuration in order to fetch the data.
--output decoded:text:udp:address=127.0.0.1,port=4809X [X=0-9]

The server aggregates 'dumpvdl2' decoder program data from participating stations.
* As with other similar projects, if many stations participate the better the result will be.

* Monitors for "unknown" VDL2 Ground Station address in latest 'VDL2_Ground_Stations' list.
(regardless of the file version the station is using)

* Notifies the VDL2 GS list maintainer with the corresponding information,
  who does the "processing" in order to "resolve" the Ground Station location.

* Note that 'vdl2info.net' server also aggregates VDL2 decoded data from
  'MultiPSK' and 'vdlm2dec' decoder programs  for the same purpose.

Additionally
============
If participating station owner enables, server offers:

* web based 'Enriched log' live streaming with message filters;
shows detailed information of Airports, Alternate and Replacement Ground Stations,

* a feature for owner to download the station's enriched log files; sets the Access Key,

* and optionally, Automatic Updating of station's VDL2 GS list -AND- BaseStation database.
#*# Instructions in '~/vdl2monitor/auto-updates.txt' file

Requirement
===========
The program is compiled to run under a Debian derivative Operating System.
Supports 'ARMv7|8' processors [RaspBerry Pi and CPU compatible Boards] (32|64Bit)
and 'Intel x86-64' processor boards (64Bit Operating Systems)

Installation [requires root privileges]
============
#*#  IF 'sudo' is not permitted to your user account switch to root user First

Step 1: Download and install vdl2monitor service
======
$ bash -c "$(wget -O - https://vdl2info.net/updown/Decoders/dmp2.sh)"
    If this fails with "certification error", try again with:
$ bash -c "$(wget --no-check-certificate -q -O - https://vdl2info.net/updown/Decoders/dmp2.sh)"

Step 2: Configure the vdl2monitor participation requirements
======
$ sudo nano /etc/default/vdl2monitor

Step 3: Setup cooperation of dumpvdl2 with vdl2monitor service
======
$ sudo nano /etc/default/dumpvdl2

[Add a new dumpvdl2 output option as bellow]
--output decoded:text:udp:address=127.0.0.1,port=4809X (X=0-9, defined at Step#2)

[Add, if not already specified, log option '--utc']

NOTE:
====
If your dumpvdl2 service is configured with 'OPTIONSn= ..." use a free OPTIONSn (n=0-9) for vdl2monitor.
e.g. OPTIONS7= --output decoded:text:udp:address=127.0.0.1,port=4809X (X=0-9, defined at Step#2)

[Restart dumpvdl2 program]
$ sudo systemctl stop dumpvdl2
$ sudo systemctl start dumpvdl2

Check dumpvdl2 restarted normally AND the new output option is activated
$ systemctl -l -n 100 status dumpvdl2 | more

IMPORTANT:
*********

Check if you are running a 64Bit version of operating system:
$ uname -m

If result shows 'aarch64' or 'arm64' overwrite the vdl2monitor executable:
$ cd ~/vdl2monitor
$ sudo cp -f vdl2monitor64 /usr/local/bin/vdl2monitor

If result shows 'x86_64' overwrite the vdl2monitor executable:
$ cd ~/vdl2monitor
$ sudo cp -f vdl2monitor_x86_64 /usr/local/bin/vdl2monitor

Finally...
Start the service -> Check service status.

Optionally Set the service permanent. It will auto-Start on reboot
and will auto-Restart upon a runtime failure.

*#* Watch your participation status at "https://vdl2info.net/" pages.

Start the service
=================
$ sudo systemctl start vdl2monitor

Check service status
====================
$ journalctl -u vdl2monitor -r
($ systemctl -l -n 100 status vdl2monitor | more)

Stop the service
================
$ sudo systemctl stop vdl2monitor

Set the service permanent flag
==============================
$ sudo systemctl enable vdl2monitor

#*#  Caution: After this step, if the service fails during runtime,
#*#  =======    it will Automatically be Restarted.  To resolve any runtime issue:
#*#  Stop the service. Check the service status for guidance, fix it and Start it again.

Clear the service permanent flag
================================
$ sudo systemctl disable vdl2monitor

UNinstallation [requires root privileges]
==============
#*#  IF 'sudo' is not permitted to your user account switch to root user First

$ cd ~
$ vdl2monitor/uninstall.sh
$ rm -rf vdl2monitor/

References
==========
'dumpvdl2' by Tomasz Lemiech  <https://github.com/szpajder/dumpvdl2>
'MultiPSK' by Patrick Lindecker  <http://f6cte.free.fr/index_anglais.htm>
'vdlm2dec' by Thierry Leconte  <https://github.com/TLeconte/vdlm2dec>

Watch for useful information: 'acars-vdl2 group' <https://acars-vdl2.groups.io/g/main>

verion 0.7beta (May 2025)
Written by Dimitris Georgiou