MLAT not syncing nor working

FlightAware ADS-B Flight Tracking
1

Hello Fellow Feeders,

I have been struggling to get MLAT to work on my setup.

Here is a little info on what i am using in terms of Hardware.

RTL-SDR v4 -

1090 filter - ADS-B Exchange Saw Filter

1090 Antenna - 5.5dBi 1090/978 N-Type Female Antenna - 26-inch (ADS-B Exchange one)​

Pc - Intel Nuc i5 16GB of RAM - Ubuntu v24 (Latest)

Unit has 4 USB-3 Ports and i am only using one for my receiver

In my dump1090-fa config file (/etc/default/dump1090-fa) i have added my Lat/Long

My cpu has a lot of room. 90% of its overhead is empty.

​

top - 21:16:54 up 26 min,  2 users,  load average: 0.01, 0.02, 0.00

Tasks: 231 total,   1 running, 230 sleeping,   0 stopped,   0 zombie

%Cpu(s):  1.2 us,  0.3 sy,  0.2 ni, 98.3 id,  0.0 wa,  0.0 hi,  0.0 si,  0.0 st

MiB Mem :  15866.5 total,  14302.6 free,   1053.0 used,    802.3 buff/cache

MiB Swap:   4096.0 total,   4096.0 free,      0.0 used.  14813.5 avail Mem

PID USER      PR  NI    VIRT    RES    SHR S  %CPU  %MEM     TIME+ COMMAND

1097 dump1090  15  -5   97732   8844   6624 S   4.7   0.1   1:09.60 dump1090-fa

 18 root      20   0       0      0      0 I   0.3   0.0   0:01.00 rcu_preempt

1205 tar1090   39  19   10604   3172   2248 S   0.3   0.0   0:00.51 tar1090.sh

2046 piaware   20   0   25208  15260   8424 S   0.3   0.1   0:01.37 fa-mlat-client

  1 root      20   0   23340  14588   9564 S   0.0   0.1   0:02.09 systemd

  2 root      20   0       0      0      0 S   0.0   0.0   0:00.00 kthreadd

One of the errors i get for the MLAT is “local clock source is unstable”

2

The two common reasons for MLAT failing are: the location being set inaccurately and delays in the data path - ie. low ISP bandwidth, high network contention etc.

Your hardware list is excellent and should otherwise be fine.

3

You’ve set the receiver location via the FlightAware website to only 1-2 decimal places of precision. mlat needs to know your receiver location more accurately for it to work correctly (ideally 4dp)

2 Likes
4

@geckoVN Thank you for your input. I have alerts for pings and latency on my ISP connection and everything on that level is fine.

@obj i did have it in 4dp before but it wasn’t working either that’s why i brought it down to 2, but the one thing i did do different is put the same coordinates on the receiver and on the site and that worked. Before the numbers were close, but off by a couple numbers.

now on Flightaware i get the GREEN MLAT logo and on my backend the entire bar is all green, which i believe is correct.

thank you for your input folks, much apricated.

5

Just out of curiosity, how did you install piaware and dump1090 on your system?/

6

if im not wrong i think it was through your script i did STEP 1 and 2

7

Thank you for the info.
Currently on Ubuntu 24, Debian Trixie, and RaspberryPi OS Trixie, the fa-mlat-client fails to build & run if the piaware 10.2 package is built using piaware_builder from Flightaware Github repository. The issue is python3 version.

I have forked piaware_builder from Flightaware, and did necessary modifications in my fork to make it built fa-mlat-client compatible to above noted OS. My automated install script at Github uses my fork of piaware_builder.

 

8

To get what your saying,
Run this
sudo wget -O /etc/apt/sources.list.d/abcd567a.list https://abcd567a.github.io/ubuntu24/abcd567a.list

and when you install
sudo apt install piaware
That is the forked version that works?

9

@1nv4lidus3r

One can install packages for Ubuntu 24 in two ways

OPTION-1:
The pre-built package method detailed below. (Four 4 commands).

sudo wget -O /etc/apt/sources.list.d/abcd567a.list https://abcd567a.github.io/ubuntu24/abcd567a.list 

sudo wget -O /etc/apt/keyrings/abcd567a-key.gpg https://abcd567a.github.io/ubuntu24/KEY2.gpg 

sudo apt update

sudo apt install piaware

 

These packages were built using my forked version of piaware_builder, and have a fully functional fa-mlat-client. During installation, the apt also install necessary dependencies including python3-pyasncore, required to make fa-mlat-client compatible to python3 version (3.12) available on Ubuntu 24

 

OPTION-2:
Build packages right on your Computer using source code. To do this, run following automated install script, which builds the piaware package at your Computer.

sudo bash -c "$(wget -O - https://raw.githubusercontent.com/abcd567a/piaware-ubuntu-debian-amd64/master/install-piaware.sh)"

 

The above script uses my fork of piaware_builder, successfully building & installing a working fa-mlat-client. The script also installs all necessary build tools and dependencies, including python3-pyasyncore. required to make fa-mlat-client compatible to python3 version (3.12) available on Ubuntu 24

 

 

1 Like
10

so everything seems to be working now, but at the time of writing this i think FA is down.
But that script worked, i re-ran it and rebooted the unit and changed the Lat/Long to match and now its works.

I noticed the location was different in both locations that also might have been throwing it off.

Really appreciate your help and quick response. You guys are freaking amazing

11

The location entry (lat, lon) in dump1090-fa config file /etc/default/dump1090-fa has NO effect on MLAT. It only affects the station marker and range rings on Skyaware local map at:
IP-of-Computer/skyaware/

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The cordinates (Lat, Lon) entered in Stats page (https://www.flightaware.com/adsb/stats/user/) are the one which are pulled by piaware from Flightaware Server, and used for Mlat synchronization

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Click on Screenshot to See Larger Size

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&nbs;

1 Like