Multilateration (MLAT) Beta


Hi everyone,

Next week, we’ll be releasing PiAware 2.0, which contains the ability to do multilateration (MLAT) of Mode S (non-ADS-B) aircraft. The PiAware server queries multiple PiAwares that all see the same Mode S target and the server does the math to MLAT the location of the Mode S aircraft.

Today, we’re releasing a beta for people to try the upgrade and begin running MLAT. This beta is for testing the installation/upgrade of the software, and for FlightAware to test the client/server communication, the back-end scaling, data processing, etc. Currently, the MLAT data will not be visible anywhere yet because we need this testing first before this will work at scale.

Installing the beta

If you run PiAware and know how to ssh in and use Linux, run the steps below. If you run the PiAware SD Card or don’t want to do the manual steps, you’ll be eligible for the auto-upgrade next week.

sudo service piaware stop
sudo dpkg -r fa-mlat-client
sudo wget
sudo dpkg -i piaware_2.0-3_armhf.deb

(Some of these commands may produce an error depending on what you have installed and that’s okay)

You will also need to set your exact location on your stats page.

You can always turn MLAT off on the command line (piaware-config -mlat 0 && service piaware restart) or via your stats page.

What It Will Do

  • Participate in the FlightAware MLAT network, using additional bandwidth (perhaps 20-50Kbps at peak)

  • Help FlightAware test client/server communication, back-end performance, scalability, data accuracy, and data integration

What It Won’t Do Yet (but will in the future)

  • Show MLAT data on your dump1090 web interface

  • Show MLAT data on

  • Show MLAT stats

More info about MLAT here:

piaware feeder crashing - cause MLAT?
Version 2.0-3 released and auto-updated
My recent RPi2 SD card rebuild helper list..

Giving it a try.

Quick correction:

“sudo dpkg -i piaware_1.22-3_armhf.deb” is >
sudo dpkg -i piaware_1.21-3_armhf.deb


Corrected – thanks!


Will the release of the PiAware SD card version 2.0 set MLAT “On” by default?

Does it do any checks to verify the location coords are “correct” and how precise must they be?

Will we be inviting PiAware feeders to check their locations and how?

Apologies for the questions.


Hi! This is awesome de got a lot of mode-s airplanes non position in our airspace, this is something we needed! Thanks!

Besides the pi aware, what about the flight feeders? It will update by itselfs?

We got with pipila 2 flight feeders and 2 pi aware receivers within the los cabos area, can’t wait to see mlat traffics plot also there is going to be a way to see them on virtual radar server ?



I followed the install/upgrade instructions and all appears to have completed successfully. But /tmp/piaware.out still reports version 1.20, is this normal? And is there a way I can confirm the new version is running?

The command [sudo piaware -v] reports 1.20-1.

Thank you, Tom


For a mode-S aircraft transponder to emit, it’ll have to have received a query - so this MLAT will only work within the range and coverage of an existing SSR?
Also it’d only work in places where you have multiple piAwares close to each other (a few miles)?
What precision of location do you expect to achieve?


I wanted to try but I forgot that I used not the standard piaware package. During my feeder time I changed my raspberry and used a mac change function in piaware from obj. If I try this version now, I create a new site…
Is there another way to use my old site?


I still show 1.20 also


Thank you. It would be nice to at least verify that I’m running the new beta version. Perhaps there is another way.


will be updating this in the next two hours.

k6rtm - you ready to light up the bay area? :smiley:


I checked the piaware log ‘cat /tmp/piaware.out’ and found the ‘multilateration support enabled’ line. So, this may be one way of checking that the beta version is being used.

05/31/2015 16:59:14 connecting to FlightAware
05/31/2015 16:59:15 FlightAware server SSL certificate validated
05/31/2015 16:59:15 encrypted session established with FlightAware
05/31/2015 16:59:15 autoUpdate is not configured in /etc/piaware or by piaware-config
05/31/2015 16:59:15 manualUpdate is not configured in /etc/piaware or by piaware-config
05/31/2015 16:59:15 multilateration support enabled (use piaware-config to disable)
05/31/2015 16:59:15 ADS-B data program ‘dump1090-muta’ is listening on port 30005, so far so good
05/31/2015 16:59:15 i see dump1090-muta serving on port 10001
05/31/2015 16:59:15 connecting to dump1090-muta on port 10001…



Sorry there is a bug and it’s reporting the wrong version. We’ll actually release v2.0-beta shortly and correct that. However, yes, it’ll mention multilateration in the logs if it’s working right.


Yes, thank you, I found that line in my piaware.out log.


I think there’s a variety of potential criteria, including being interrogated by other TCAS aircraft.

Also it’d only work in places where you have multiple piAwares close to each other (a few miles)?

Within the range of all the receivers, which could mean they’re >200mi aparrt.

What precision of location do you expect to achieve?

It depends on the quality of the layout of sites that see the aircraft, but potentially almost as good as SSR.


Any chance to manually update to the MLAT version as well? I run dump1090 and piaware on an Intel based netbook. I just fetched the latest piaware from Github and compiled it. The fa-mlat-client is missing and hence MLAT support is disabled according to the print-out.

I’m already part in the mlat setup that obj has made and loving it. Any change that I can get the fa-mlat-client for Intel 32 bits so I can join the beta?



No issues with the update steps except that the service was restarted (presumably) after the update without the need for a separate command to restart the service. The remove step failed predictably but it did not affect the overall update experience.

The assigned RPi was updated/upgraded duly prior to applying the MLAT update. CPU utilization is still around 25% with the 05/05 Raspbian Wheezy. I wish I could let the CPU do some other ***piaware ***tasks to chew a few more CPU cycles every now and then. Rgds. :slight_smile:


Everything seemed to be working but I couldn’t really see any difference until after a reboot. Then fa_mlat-client appeared in top. Starting and stopping the client wasn’t enough.


Had to resolve some missing packages via

apt-get install -fy

(Yes, I purged python 3, running on minibian and I’m still coding for python 2, guess I need to get with it…)


definitely noticing a higher message count (per 5min) after the update.

[2015-05-31 11:03 PDT] 8805391 msgs recv’d from dump1090 (783 in last 5m); 8800593 msgs sent to FlightAware
[2015-05-31 11:26 PDT] 4574 msgs recv’d from dump1090 (1246 in last 5m); 4573 msgs sent to FlightAware