thebaldgeek

Rough notes on how to go about setting up the hardware and software for ACARS decoding.

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Aircraft Communication Addressing and Reporting System.

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ACARS is the messaging system that allows aircraft talk to and from the ground staff / systems.

There are two main ACARS modes on VHF.
ACARS between 129 Mhz and 131 Mhz. (Doh! Just outside the 2Mhz span of a singe RTL SDR)
VDL2 between 136.6 Mhz and 136.9 Mhz.
Roughly you can think of ACARS as slightly older analog and VDL2 as digital.

The two different modes are in use to different amounts all over the world, its imposable for us (yet - the data will soon be there for us to say with more confidence) to tell you which to pick for your location. I suggest that you install both packages, run both for a week and compare numbers for your location. Perhaps, like me in California, both have high message rates on both modes and you will end up running a few SDR dongles. (I run 3 in the one Pi 3. Two for ACARS and one for VDL2).

The other ‘fun’ part here is that if the full spread of ACARS frequencies are in use in your location, it will be too wide for a single RTLSDR bandwidth, so if they are and you want to catch all the data (please and thank-you), then you will need to run two dongles, a lower set of frequencies on one and the higher set on the other.
So, a full setup might consist of 2 x ACARS SDR and 1 x VDL2 SDR.

Hardware BOM (Bill of materials)

Note, be very careful about running a VHF LNA. ACARS is close to the FM band and you may easily overload the RF front end of the SDR and make things worse. Look at your SDR waterfall software if you can to see what the RF interference in your area is like and see how well you are picking up the ACARS/VDL bursts. Most of the usual SDR software package have a waterfall feature where you can see a chunk of your frequency of interest.
I personally have had both success and failure running the GPIO filtered airband LNA. In one location it was great and made a worthy addition, in another it made the signal useless. It was an expensive test. Your milage may vary.

Serialize your SDRs before you start

If you have more than one SDR and you jump right in and install the software, you are going to get frustrated. The decoders start up as soon as they are installed and will grab the first open SDR it can find. This may or may not be the SDR you want. So how can we tell each decoder (even ADSB or UAT) to use the correct SDR connected to the correct antenna? By setting different serial numbers in each SDR dongle.
Because of course every SDR has the same serial number out of the box. Usually 000000000000000001 (I can never count how many zeros there are….. too many frankly) or if its an orange one it might have 978 or something else, and if its a blue one it might have 1090 or something else.

How to find your current serial numbers

Plug in any SDRs you want with any software currently running. We are going to have to break a few eggs to make things right.
Once you have done that, type at the linux command line rtl_test
You will see something like this come back:

pi@acars-kriv:~ $ rtl_test  
Found 3 device(s):  
0:  Realtek, RTL2832U, SN: 978  
1:  Realtek, RTL2838UHIDIR, SN: 00000001  
2:  Realtek, RTL2838UHIDIR, SN: 00000001  

Using device 0: Generic RTL2832U
usb_claim_interface error -6
Failed to open rtlsdr device #0.

Ok, so what do we have here?
You can see the device id on the left, this matters because most decoders will use that, next the type and last the serial number.
We have an orange (dev 0, sn 978) and two RTL’s with their default serials.
And the error at the bottom is because the ‘rtl_test’ command tries to grab a free SDR to test it, so since they are all in use, it gets grumpy - just ignore it for now.
Lets fix it shall we.
The way you change the SDR serial is to use the rtl_eeprom command.
Since everything is already plugged in, lets just ‘mow the lawn’ and fix those too many zero serial numbers. In my case, I would do the following:
rtl_eeprom -d 1 -s 131
Breakdown: -d for device. 1 for device 1 from the list. -s for serial. 131 is the serial number we are going to assign to SDR device 1 from the list.
Answer Y to the ‘are you sure’ prompt. Then do the next one:
rtl_eeprom -d 2 -s 136
Answer Y to the question and we are nearly set.
If you read the prompt, it says to remove and replug to make the change, so thats a must.
What we did was to make SDR device one SN 130 (or Mhz for ACARS) and SDR device two SN 136 (or Mhz for VDL).
(If you only have one SDR you can drop the ‘-d’ part since it defaults the serial to the one and only SDR).
If you pull them both out and only plug in one, then do the rtl_test command, you can see which one you just plugged in.
LABEL IT! No really, trust me, you will forget, write on it, engrage it, put some blue tape on it and write on that. Just put the SN on it already!
If it starts testing, just hit ctrl+c to exit the test.
Plug in the next one, type up arrow to get the test command again and hit enter and see what serial it is. Label it.
Ok, now we can start installing the software….

Software

We often get the question which should you chose, ACARS or VDL. The answer depends on where you live and the aircraft traffic/age of aircraft in your area. You may have to run each for a few hours/days and just get a feel for the sorts of numbers of each modes message rate. If you can run three dongles and 1-3 antennas, pick up all you can, but 1 antenna and 1 dongle can still give really important data from your location. (Note that ACARS is like ADSB, we need lots of stations to give global coverage, so no matter where you live, we can use the data!)
Also do note that in your area perhaps not the whole spread for ACARS is in use, in this case you might just need two dongles, one for ACARS and one for VDL. So this is why I strongly suggest you test first.
Also I strongly recommend that you look at the airframes.io frequency report It can help guide you as to what is in use in your area based on data from other feeders ‘near’ you.

There is one supported decoder for ACARS and two decoders for VDL2. All of which only run on Linux. None of them have a graphic interface, so there is no need to run a desktop distro if you don’t want to. (Better if you don’t, more CPU cycles to decode with).
(There are some Windows options, Blackcat and MultiPSK, both are outside the scope of this page - neither of them can feed airframes.io).
If you know and love docker, then there is that option as well SDR Enthusiasts is a good way to combine your ADSB data with your ACARS data in your location. Do note that even with Docker it’s best to serialize your SDRs, so do that bit at the very least.

acarsdec is a multi-channel (in the same 2Mhz range) acars decoder with built-in rtl_sdr, airspy front end or sdrplay device.
vdlm2dec can decode up to 8 frequencies simultaneously (again, in the same 2Mhz range ) using the typical RTLSDR hardware. It decodes ARINC-622 ATS applications (ADS-C, CPDLC) via libacars library. It can also send VDL aircraft positions to a local VRS map if thats your thing.
dumpvdl2 Has the following features:

Airframes.io supports feeds from all three, from the two VDL2 decoders personally I like dumpvdl2 as it has a much richer output that I find very helpful (noise floor and signal strength data just to name two).

Building / Installing the Software

If you just want to get going - and who doesn’t… just go here and run the script for the decoder you want….

To find out more about feeding the main airframes.io website, check out these links:

Config help

Ok, so things are installed and they are installed as a service so will auto start after a reboot or power cycle, so lets take a look at our config options.

ACARS

Lets edit the ACARS decoder conf file first (if you are not running this, dumpvdl2 is next).

sudo nano /etc/default/acarsdec

OPTIONS0= -v -o 4 -j feed.acars.io:5550

# station name for acars.io:
OPTIONS1= -i TBG-ACARS-xxxx

# gain for rtl-sdr, for example 43.9 and -10 or 55 for AGC
OPTIONS2= -g 55

# change to -m 192 for 2.4 MS/s sample rate instead of 2.0 MS/s (might be a bit better)
OPTIONS3= -m 160

# to have the messages written to disk instead of the journal, uncomment the following line:
OPTIONS4= -v -o 4 -j 127.0.0.1:2233

# rtl-sdr device id or serial:
OPTIONS7= -r 0

# frequencies scanned:
OPTIONS8= 130.025 130.450 131.125 131.525 131.550 131.725 131.825

From the top…..

Feed aiframes.io

First up, thanks for not commenting this out and supporting the whole ACARS community by feeding airframes.

Station id

Next is the station name that will show up in airframes.io.
When this decoder starts up, it has a random name in here, you really need to change it. Please DON’T use the one in my example here, xxxx is not an airport ICAO for a start….
I really like the format of some initials (ham call sign perhaps), then the type of data, then your nearest large airport code.
Some of the guys swap the order of the airport and type, or drop the type totally. So you have options, but please think about it for yourself, chose a system of naming that works for you and stick with it. Saves the airframes guys a ton of work renaming your feeds when you change your mind. Hint. Take a look at the airframes feeder page for other examples.

Gain

Next up is the gain settings.
Default is AGC or auto gain control. This is Ok to start with, but just like ADSB, max gain is not usually the best and we will talk more about this setting and how to tune your station at some point ‘soon’.

Sample rate

Default is ok, higher sample is higher CPU use, so if your maxed out on a Pi, tweak at the risk of dropping decodes.

Node-RED feed?

Next you can chose to feed your Node-RED dashboard / logger / alerter what ever.
If you don’t want to do this, just leave it commented out.

SDR serial number

Here is an important one. You know how to check and set it now. Note its using the device ID and not the actual serial number.

Frequencies scanned

Always contentious because the old saying ‘if a little is good, more is better’ is often used, but has never proven right.
The risk of adding more here is that you are going to get bleed over and see the same message on two frequencies from close aircraft and claim that there is a ‘new unlisted frequency in use in your area’. (Im being a bit cheeky here).
Best to stick with the known list on aiframes.

Restart the service to apply changes

sudo systemctl restart acarsdec
Ok so is it working?

Show errors and aircraft messages

sudo journalctl -ef -u acarsdec

dumpVDL

sudo nano /etc/default/dumpvdl2
Here is an example of a config file for USA (frequencies will be different per location).
DUMPVDL2_OPTIONS="--rtlsdr 1 --correction 2 --gain 32 --output decoded:json:udp:address=feed.airframes.io,port=5552 --station-id xxx-VDL2-yyyy 136650000 136800000 136975000"
We are using USB device 1 here, use the ‘rtl_test’ command to get the right one for your setup. I have a little PPM correction applied (+2). Gain set to 32. Feeding data to airframes and the three main frequencies in use here in USA (Some try and listen to more frequencies and only get overloaded duplicated messages with less main decodes since every added frequency reduces CPU and SDR/USB bandwidth for the real ones - ie, more is NOT better).
Change your station id to something sensible.
A few other config examples further down the page.

Restart the service to apply changes

sudo systemctl restart dumpvdl2
Ok so is it working?

Show errors and decoded aircraft messages

sudo journalctl -ef -u dumpvdl2

Once you have your mode up and decoding to the terminal, then you can check your feed of data to airframes.io and claim your feeder (and climb the soon coming leaderboard).

Stop reading!

Both vdlm2dec and dumpvdl2 can work with Node-RED. In fact they are very similar to install and use. They both output their data in JSON but only dumpvdl2 has a decoded text option.
Part of the problem with both of them is that neither author lists all the options of the JSON keys their programs can produce in their docs, this makes it hard for me to write a Node-RED flow that can intelligently deal with unknown keys as they come across the wire. I’m sure if you dug into their code they would probably have an array somewhere in a file that lists all the possible key pairs that their program could show in an given message. I’m also sure that if you knew how to program there is probably a well known method to deal with random key pairs in your code.

Note that vdlm2dec requires its command line frequencies to be in Mhz while dumpvdl requires them to be in Hz.

Feeding VDL2 data to Node-RED
Both programs (well, all three if you count the ACARS decoder) will take a command line option to stream the decoded message via UDP. I simply point that stream to my hostname:port and have a UDP in node listening on that port.

I hope to add a Node-RED ACARS example flow to this page ‘soon’.

dumpvdl

Here is a partial flow will display some of the main text values that come in on a decoded text stream from dumpvdl.

[{"id":"27278a8d.356866","type":"udp in","z":"5e5fdc91.d8f9d4","name":"Uk","iface":"","port":"112233","ipv":"udp4","multicast":"false","group":"","datatype":"utf8","x":2040,"y":1380,"wires":[["85112668.5314d8","63e7b7fa.3dbca8","ae622b78.e1ec48","ae6e4362.9c512","a4d431d5.84261"]]},{"id":"85112668.5314d8","type":"msg-speed","z":"5e5fdc91.d8f9d4","name":"","frequency":"min","estimation":false,"ignore":false,"x":2210,"y":1380,"wires":[["dd053c0a.85401"],["b01b47b.d90c2b8","9a9f2355.0e9eb"]]},{"id":"b01b47b.d90c2b8","type":"switch","z":"5e5fdc91.d8f9d4","name":"frequency counter","property":"payload","propertyType":"msg","rules":[{"t":"cont","v":"136.725","vt":"str"},{"t":"cont","v":"136.775","vt":"str"},{"t":"cont","v":"136.800","vt":"str"},{"t":"cont","v":"136.975","vt":"str"},{"t":"else"}],"checkall":"false","repair":false,"outputs":5,"x":2450,"y":1340,"wires":[["7e35bf77.81579"],["bddb221b.8cf9d"],["fa937852.523268"],["4ca4ddca.ab0714"],[]]},{"id":"7e35bf77.81579","type":"counter","z":"5e5fdc91.d8f9d4","inc":"1","name":"","x":2675,"y":1260,"wires":[["ebf306d.eeed3f8"]],"l":false},{"id":"bddb221b.8cf9d","type":"counter","z":"5e5fdc91.d8f9d4","inc":"1","name":"","x":2675,"y":1300,"wires":[["dd625424.044428"]],"l":false},{"id":"63e7b7fa.3dbca8","type":"debug","z":"5e5fdc91.d8f9d4","name":"","active":true,"tosidebar":true,"console":false,"tostatus":false,"complete":"false","statusVal":"","statusType":"auto","x":2210,"y":1460,"wires":[]},{"id":"fa937852.523268","type":"counter","z":"5e5fdc91.d8f9d4","inc":"1","name":"","x":2675,"y":1340,"wires":[["b09868e3.aa1528"]],"l":false},{"id":"4ca4ddca.ab0714","type":"counter","z":"5e5fdc91.d8f9d4","inc":"1","name":"","x":2675,"y":1380,"wires":[["927bfee8.ebf32"]],"l":false},{"id":"dd053c0a.85401","type":"ui_text","z":"5e5fdc91.d8f9d4","group":"a38ae90b.462a58","order":2,"width":1,"height":1,"name":"","label":"msg per min: ","format":"","layout":"row-left","x":2458,"y":1227,"wires":[]},{"id":"927bfee8.ebf32","type":"ui_text","z":"5e5fdc91.d8f9d4","group":"a38ae90b.462a58","order":7,"width":2,"height":1,"name":"","label":"136.975 = ","format":"","layout":"row-left","x":2810,"y":1380,"wires":[]},{"id":"b09868e3.aa1528","type":"ui_text","z":"5e5fdc91.d8f9d4","group":"a38ae90b.462a58","order":5,"width":2,"height":1,"name":"","label":"136.800 = ","format":"","layout":"row-left","x":2800,"y":1340,"wires":[]},{"id":"ebf306d.eeed3f8","type":"ui_text","z":"5e5fdc91.d8f9d4","group":"a38ae90b.462a58","order":1,"width":2,"height":1,"name":"","label":"136.725 = ","format":"","layout":"row-left","x":2800,"y":1260,"wires":[]},{"id":"dd625424.044428","type":"ui_text","z":"5e5fdc91.d8f9d4","group":"a38ae90b.462a58","order":3,"width":2,"height":1,"name":"","label":"136.775 = ","format":"","layout":"row-left","x":2800,"y":1300,"wires":[]},{"id":"9a9f2355.0e9eb","type":"counter","z":"5e5fdc91.d8f9d4","inc":"1","name":"","x":2675,"y":1420,"wires":[["8772957f.b74d78"]],"l":false},{"id":"8772957f.b74d78","type":"ui_text","z":"5e5fdc91.d8f9d4","group":"a38ae90b.462a58","order":4,"width":1,"height":1,"name":"","label":"Total: ","format":"","layout":"row-left","x":2790,"y":1420,"wires":[]},{"id":"a38ae90b.462a58","type":"ui_group","name":"UK","tab":"733f36e1.cf5db8","order":7,"disp":true,"width":3,"collapse":false},{"id":"733f36e1.cf5db8","type":"ui_tab","name":"VHF-VDL2","icon":"flight","order":7,"disabled":false,"hidden":false}]

vdlm2dec

Even though I don’t use it since I cant handle the random JSON keys, here is a partial flow that displays some of the main key value pairs for vdlm2dec via JSON.

[{"id":"27278a8d.356866","type":"udp in","z":"5e5fdc91.d8f9d4","name":"Uk","iface":"","port":"112233","ipv":"udp4","multicast":"false","group":"","datatype":"utf8","x":2030,"y":1380,"wires":[["85112668.5314d8","4c65059e.1c8c4c"]]},{"id":"85112668.5314d8","type":"msg-speed","z":"5e5fdc91.d8f9d4","name":"","frequency":"min","estimation":false,"ignore":false,"x":2210,"y":1380,"wires":[["dd053c0a.85401"],["b01b47b.d90c2b8","9a9f2355.0e9eb"]]},{"id":"b01b47b.d90c2b8","type":"switch","z":"5e5fdc91.d8f9d4","name":"frequency counter","property":"payload","propertyType":"msg","rules":[{"t":"cont","v":"136.650","vt":"num"},{"t":"cont","v":"136.725","vt":"num"},{"t":"cont","v":"136.775","vt":"num"},{"t":"cont","v":"136.800","vt":"num"},{"t":"cont","v":"136.825","vt":"num"},{"t":"cont","v":"136.875","vt":"num"},{"t":"cont","v":"136.975","vt":"num"},{"t":"else"}],"checkall":"false","repair":false,"outputs":8,"x":2450,"y":1340,"wires":[["ce4baf35.883c4"],["7e35bf77.81579"],["bddb221b.8cf9d"],["fa937852.523268"],["19528aa2.bd25f5"],["3ccff35e.aac23c"],["4ca4ddca.ab0714"],[]]},{"id":"ce4baf35.883c4","type":"counter","z":"5e5fdc91.d8f9d4","inc":"1","name":"","x":2675,"y":1220,"wires":[["534ea04c.ea31"]],"l":false},{"id":"7e35bf77.81579","type":"counter","z":"5e5fdc91.d8f9d4","inc":"1","name":"","x":2675,"y":1260,"wires":[["ebf306d.eeed3f8"]],"l":false},{"id":"bddb221b.8cf9d","type":"counter","z":"5e5fdc91.d8f9d4","inc":"1","name":"","x":2675,"y":1300,"wires":[["dd625424.044428"]],"l":false},{"id":"63e7b7fa.3dbca8","type":"debug","z":"5e5fdc91.d8f9d4","name":"","active":true,"tosidebar":true,"console":false,"tostatus":false,"complete":"false","statusVal":"","statusType":"auto","x":2150,"y":1540,"wires":[]},{"id":"fa937852.523268","type":"counter","z":"5e5fdc91.d8f9d4","inc":"1","name":"","x":2675,"y":1340,"wires":[["b09868e3.aa1528"]],"l":false},{"id":"19528aa2.bd25f5","type":"counter","z":"5e5fdc91.d8f9d4","inc":"1","name":"","x":2675,"y":1380,"wires":[["df38d989.ddb808"]],"l":false},{"id":"3ccff35e.aac23c","type":"counter","z":"5e5fdc91.d8f9d4","inc":"1","name":"","x":2675,"y":1420,"wires":[["53a473c3.ca150c"]],"l":false},{"id":"4ca4ddca.ab0714","type":"counter","z":"5e5fdc91.d8f9d4","inc":"1","name":"","x":2675,"y":1460,"wires":[["927bfee8.ebf32"]],"l":false},{"id":"dd053c0a.85401","type":"ui_text","z":"5e5fdc91.d8f9d4","group":"a38ae90b.462a58","order":17,"width":1,"height":1,"name":"","label":"msg per min: ","format":"","layout":"row-left","x":2458,"y":1227,"wires":[]},{"id":"927bfee8.ebf32","type":"ui_text","z":"5e5fdc91.d8f9d4","group":"a38ae90b.462a58","order":19,"width":2,"height":1,"name":"","label":"136.975 = ","format":"","layout":"row-left","x":2800,"y":1460,"wires":[]},{"id":"534ea04c.ea31","type":"ui_text","z":"5e5fdc91.d8f9d4","group":"a38ae90b.462a58","order":1,"width":2,"height":1,"name":"","label":"136.650 = ","format":"","layout":"row-left","x":2800,"y":1220,"wires":[]},{"id":"b09868e3.aa1528","type":"ui_text","z":"5e5fdc91.d8f9d4","group":"a38ae90b.462a58","order":2,"width":2,"height":1,"name":"","label":"136.800 = ","format":"","layout":"row-left","x":2800,"y":1340,"wires":[]},{"id":"ebf306d.eeed3f8","type":"ui_text","z":"5e5fdc91.d8f9d4","group":"a38ae90b.462a58","order":7,"width":2,"height":1,"name":"","label":"136.725 = ","format":"","layout":"row-left","x":2800,"y":1260,"wires":[]},{"id":"dd625424.044428","type":"ui_text","z":"5e5fdc91.d8f9d4","group":"a38ae90b.462a58","order":13,"width":2,"height":1,"name":"","label":"136.775 = ","format":"","layout":"row-left","x":2800,"y":1300,"wires":[]},{"id":"df38d989.ddb808","type":"ui_text","z":"5e5fdc91.d8f9d4","group":"a38ae90b.462a58","order":8,"width":2,"height":1,"name":"","label":"136.825 = ","format":"","layout":"row-left","x":2800,"y":1380,"wires":[]},{"id":"53a473c3.ca150c","type":"ui_text","z":"5e5fdc91.d8f9d4","group":"a38ae90b.462a58","order":14,"width":2,"height":1,"name":"","label":"136.875 = ","format":"","layout":"row-left","x":2800,"y":1420,"wires":[]},{"id":"4c65059e.1c8c4c","type":"json","z":"5e5fdc91.d8f9d4","name":"","property":"payload","action":"","pretty":false,"x":2190,"y":1480,"wires":[["63e7b7fa.3dbca8","f8d13f15.5590c","527949ed.e9eb68","b6253ede.f08e3","102aaa94.c920d5","eda5e162.ec41c","6efac09a.a2f69"]]},{"id":"f8d13f15.5590c","type":"function","z":"5e5fdc91.d8f9d4","name":"icao","func":"msg.icaoString = msg.payload.icao.toString(16);\nmsg.gsid = msg.payload.toaddr.toString(16);\nreturn msg;","outputs":1,"noerr":0,"initialize":"","finalize":"","libs":[],"x":2410,"y":1460,"wires":[["62c4d94f.b25828","7d3510bb.8054b"]]},{"id":"62c4d94f.b25828","type":"ui_text","z":"5e5fdc91.d8f9d4","group":"a38ae90b.462a58","order":4,"width":1,"height":1,"name":"","label":"ICAO: ","format":"","layout":"row-left","x":2550,"y":1460,"wires":[]},{"id":"7d3510bb.8054b","type":"ui_text","z":"5e5fdc91.d8f9d4","group":"a38ae90b.462a58","order":10,"width":1,"height":1,"name":"","label":"GS ID: ","format":"","layout":"row-left","x":2544,"y":1497,"wires":[]},{"id":"527949ed.e9eb68","type":"ui_text","z":"5e5fdc91.d8f9d4","group":"a38ae90b.462a58","order":5,"width":2,"height":1,"name":"","label":"Tail: ","format":"","layout":"row-left","x":2550,"y":1540,"wires":[]},{"id":"b6253ede.f08e3","type":"ui_text","z":"5e5fdc91.d8f9d4","group":"a38ae90b.462a58","order":11,"width":2,"height":1,"name":"","label":"Flight: ","format":"","layout":"row-left","x":2550,"y":1580,"wires":[]},{"id":"102aaa94.c920d5","type":"ui_text","z":"5e5fdc91.d8f9d4","group":"a38ae90b.462a58","order":16,"width":6,"height":1,"name":"","label":"Data: ","format":"","layout":"row-left","x":2550,"y":1620,"wires":[]},{"id":"eda5e162.ec41c","type":"ui_text","z":"5e5fdc91.d8f9d4","group":"a38ae90b.462a58","order":21,"width":6,"height":1,"name":"","label":"Text: ","format":"","layout":"row-left","x":2550,"y":1660,"wires":[]},{"id":"6efac09a.a2f69","type":"function","z":"5e5fdc91.d8f9d4","name":"","func":"msg.ts = new Date(msg.payload.timestamp * 1000);\nmsg.ts = msg.ts.toISOString().slice(msg.ts.length,-5);\nreturn msg;","outputs":1,"noerr":0,"initialize":"","finalize":"","libs":[],"x":2435,"y":1700,"wires":[["76d49f7b.2597e"]],"l":false},{"id":"76d49f7b.2597e","type":"ui_text","z":"5e5fdc91.d8f9d4","group":"a38ae90b.462a58","order":6,"width":3,"height":1,"name":"","label":"Last msg: 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Ok, you kept reading…. Here is your reward.

Plotting dumpvdl position data on a map

Yes, its possible to plot dumpVDL positions on a map like VRS. If you are using vdl2dec, just use the -s option and setup an SBS receiver on your local VRS.
If you are using dumpvdl, the flow outline goes like this…. Use Node-RED to get the lat/lon data out of any dumpvdl aircraft messages and convert them into VRS ‘basestation’ format and then add a new receiver to tar10909 or VRS to take the UDP data flow from that Node-RED code.
The interesting part is that the JSON output from dumpvdl can have any one of (so far I have logged) 12,000 keys. Of those 12,000 I have found around 640 that have aircraft lat/lon data in them. Finding and plotting those is your challenge. I don’t know how many of those 640 the vdl2dec is using to plot its positions.
Here is a screenshot from a guy in Ireland that is running such a flow in his Raspberry Pi that is also doing the dumpvdl decoding.


All these aircraft are from the dumpvdl decoder with position data in their ACARS messages.
ACARS position plotting is a bit tricky to do, but we are working on it and of course dumphfdl already provides a tar1090 / VRS basestation output, so thats very easy to get plotting and does not require any Node-RED at all.

Build from source

Ok, hardcore linux guys, this is for you…. You can script the following commands, but I like to copy paste each one to ensure it runs without error.
If you are installing on an existing ADSB setup, you can skip the first part since you already have the SDR drivers installed and working.

No matter if you have an existing ADSB or clean install, the first step is to update your system and install the required packages. All the following need to be done as root, so lets become sudo….
sudo su

apt-get update

apt-get install -y cmake rtl-sdr git cmake libusb-1.0-0-dev libtool librtlsdr-dev build-essential libglib2.0-dev pkg-config librtlsdr-dev libxml2-dev libzmq3-dev python3-zmq zlib1g-dev libxml2-dev

ldconfig

If you have SDR software installed all ready, skip this section.
cd /usr/src
git clone https://github.com/osmocom/rtl-sdr.git
cd rtl-sdr
mkdir build
cd build
cmake ../ -DINSTALL_UDEV_RULES=ON -DDETACH_KERNEL_DRIVER=ON
make -j3
make install
ldconfig
cd /usr/src/rtl-sdr
cp rtl-sdr.rules /etc/udev/rules.d/

Now we install the libacars package. This is needed to decode the rich ACARS messages like ARINC622.
cd /usr/src
git clone --depth=1 https://github.com/szpajder/libacars
cd libacars
mkdir build
cd build
cmake ../
make -j3
make install
ldconfig

Now lets install the acarsdec package.
cd /usr/src
git clone --depth=1 https://github.com/TLeconte/acarsdec.git
cd acarsdec
mkdir build
cd build
cmake .. -Drtl=ON
make -j3
make install

Now lets install the dumpvdl2 package.
cd /usr/src
git clone --depth=1 https://github.com/szpajder/dumpvdl2.git
cd dumpvdl2
mkdir build
cd build
cmake ../
make -j3
make install
cd ..
cp etc/dumpvdl2.service /etc/systemd/system/
cp etc/dumpvdl2 /etc/default/
systemctl daemon-reload

Lastly, reboot and plug in your ACARS SDR dongle(s).
reboot now

Here is an example command to listen on a few VDL frequencies (check out airframes.io/about for a good list of VDL2 frequencies to listen on in your part of the world.

dumpvdl2 --rtlsdr -0 --gain 42 136725000 136775000 136800000 136975000

Once you are happy with the output you can then setup dumpvdl2 to launch in the background and when the Pi boots:

sudo nano /etc/default/dumpvdl2
In that file, uncomment the DUMPVDL2_OPTIONS= and put your options from the test you just ran in to the file, save and exit it - it will look something like this:

DUMPVDL2_OPTIONS="--rtlsdr -0 --gain 42 --correction 7 --output decoded:text:udp:address=yourWebSite.com,port=112233 136725000 136775000 136800000 136975000"

Here is an example command line that will filter out empty system pings and handshakes and log data to a dead log file that will never be used:
dumpvdl2 --msg-filter all,-avlc_s,-acars_nodata,-gsif,-x25_control,-idrp_keepalive,-esis --rtlsdr 2 --gain 40 --correction -1 --output decoded:text:file:path=vdl.log,rotate=hourly 136650000 136975000 136800000

Here is an example command to listen on a few ACARS fequenices:
acarsdec -v -o 4 -g 280 -r 0 131.550 131.525 131.725 131.825 130.025 130.425 130.450 131.125

Do note that none of this runs as a serice so will need restarting after a power cycle or reboot.