FlightAware Discussions

Airspy no MLAT

Folks I debated whether to revive "MLAT Enabled No MLAT "but the thread was 3 years old
and I guess it would have spammed all the contributors - possibly to their annoyance!

I have a couple of RPi4: one with FA blue Pro Stick Plus dongle and the other an Airspy Mini dongle.
Same amplified signal is fed to both systems via a cavity splitter.
The Airspy is my experimentation system and has only recently been installed.

Location is precisely set on both systems and I don’t notice errors or bad performance on either.

For reasons I do not understand, the Airspy system is not launching /usr/lib/piaware/helpers/fa-mlat-client (as if mlat has been disabled). Consequently I see a more “OTHER” for Airspy (RHS picture above)

Strangely I see a green MLAT synchronised:


But dipping into the various files I notice…

pi@piaware:~ $ cat /run/piaware/status.json
“uat_enabled” : false,
“piaware” : {
“status” : “green”,
“message” : “PiAware 3.8.1 is running”
“expiry” : 1586355510171,
“interval” : 5000,
“mlat” : {
“status” : “red”,
“message” : “Multilateration is not enabled”
“modes_enabled” : true,
“adept” : {
“status” : “green”,
“message” : “Connected to FlightAware and logged in”
“radio” : {
“status” : “green”,
“message” : “Received Mode S data recently”
“site_url” : “https://flightaware.com/adsb/stats/user/hphillip#stats-123922”,
“time” : 1586355499171

…confirming status red for MLAT

As an experiment, I tried manually launching fa-mlat-client (but I’m certainly not clear if the parameters are correct or even appropriate) and I see…

pi@piaware:~ $ /usr/lib/piaware/helpers/fa-mlat-client --input-connect localhost:30005 --input-type dump1090 --results beast,connect,localhost:30104 --results beast,listen,30105 --results ext_basestation,listen,30106 --udp-transport
fa-mlat-client 0.2.11 starting up
Using UDP transport to port 13235
Listening for Beast-format results connection on port 30105
Listening for Extended Basestation-format results connection on port 30106
Route MTU changed to 1500
type mlat_event event ready mlat_client_version 0.2.11 capabilities anon modeac
Input connected to localhost:30005
Input format changed to BEAST, 12MHz clock
type mlat_event event connected
type mlat_event event clock_reset reason Decoder mode changed to BEAST frequency 12000000 epoch none mode BEAST
Beast-format results connection with ::1:30104: connection established
type mlat_seen hexids AE6043 491D85 34324F 407698 43C09A 43C55F AA01A2 06A1A5 7608EA 01012A 06A12A 4076EB 43C171 3C5432 407277 A1B4B9 4CA27C A6E03F
type mlat_rates rates 491D85 1.72 407277 1.90 43C171 1.87 43C09A 1.40 AA01A2 1.75 407698 1.81 7608EA 1.87 A6E03F 1.62 A1B4B9 1.82 01012A 1.69 4CA27C 1.75 06A1A5 1.88 34324F 1.47 06A12A 1.60 4076EB 0.85 3C5432 1.14
type mlat_udp_report messages_sent 0
type mlat_seen hexids 4BB150
type mlat_rates rates 491D85 1.94 407277 1.94 43C171 1.88 43C09A 1.88 AA01A2 1.94 407698 1.91 7608EA 2.07 A6E03F 1.66 A1B4B9 1.85 01012A 0.73 4CA27C 1.88 06A1A5 1.85 34324F 1.88 06A12A 1.59 4076EB 1.47 3C5432 1.43
type mlat_seen hexids 43C7CF
type mlat_rates rates 491D85 1.94 407277 1.97 43C171 2.00 43C09A 1.88 AA01A2 1.94 407698 1.97 7608EA 1.91 A6E03F 1.78 A1B4B9 1.53 01012A 1.27 4CA27C 1.72 06A1A5 1.94 34324F 1.62 06A12A 0.64 4076EB 1.40 3C5432 1.59 4BB150 1.00

…which suggests potentially I should be able to enable the MLAT and get it working.

I just don’t know how to enable the mlat on this Airspy installation!

If I set the MLAT enabled radio button on the Site Configuration it appears to do nothing.
Next time the dialog loads it has been reset to MLAT disabled.

Beginning to clutch at straws.
Does anyone have any suggestions for a fix without having to do a complete re-install?
Any advice much appreciated.

What command are you using to run airspy?
What are the settings for dump1090-fa?

sudo piaware-config

Maybe just reboot?

I have rebooted many times to no avail :frowning:

I used the recommended install script…

Parameters passed to airspy_adsb are:

/usr/local/bin/airspy_adsb -v -f 1 -l 47787:beast -g 15 -m 12

Parameters passed to dump1090-fa are…

… truncated in the above pic, but with the exception of my blah substitution, they are actually…

/usr/bin/dump1090-fa --net-only --max-range 360 --fix --net --net-heartbeat 60 --net-ro-size 1300 --net-ro-interval 0.2 --net-http-port 0 --net-ri-port 0 --net-ro-port 30002 --net-sbs-port 30003 --net-bo-port 0 --net-bi-port 30004,30104 --json-location-accuracy 2 --lat 51.blah --lon -1.83blah --write-json /run/dump1090-fa --quiet

Last but not least, piaware-config

Perhaps I have a port number wrong somewhere?

You have mlat disabled in the site configuration for site #123922 (on the website side of things)

I refer to my previous comment :wink:

However many times I set it to enabled it does not stick!

Aha, ok, I missed that, sorry. Let me have a poke at it; that setting is the cause of the problem.

Thank you. That’s great.
Much appreciated.

OK, it’s a problem with the recent control panel overhaul I think; the “save” button isn’t appearing if you change some settings, so your changes get lost. I think I managed to convince it to update your mlat settings by also changing some other settings at the same time (then changing them back) so that I could get a save button to appear; I’ll raise a bug report for the missing save button.


That’s fantastic @Obj. Really appreciated that you were able to respond so quickly and confirm it is indeed a bug, rather than something stupid I was doing!

Thank you also to wiedehopf and jonhawkes2030 for your suggestions


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