"Noise" in MLAT tracks after upgrading to Pi 3


#1

G’day, all;

After getting several “anomaly” reports from the stats page that my Pi B (original model) CPU usage was being over-taxed, I upgraded to a Pi 3.

Since then, many of the tracks have been showing a lot of “noise” in their positions.

Image at: http://imgur.com/a/wS10Q

Did I do something to screw up the timing?

Thanks!


#2

Are you doing mlat other than FA mlat? Generally, trying to combine two sources of mlat results produces things like this because the two sources disagree on exactly where the aircraft is.


#3

I added ADS-B Exchange to my feed (using their setup scripts). Is that screwing up my data? Should I revert to the standard PiAware software and stop feeding others?

Thanks!


#4

You don’t have to stop feeding them but trying to display both their mlat results and FA’s mlat results at the same time isn’t going to work well.


#5

Thanks for the reply. Is there a way to filter the display so as to see only one or the other? (I’m a bit new to the ADS-B game, although I’m pretty handy at Linux and RF-related hardware).


#6

I don’t know what their setup scripts do; you’d need to ask how to disable their stuff on their forums.


#7

If you want to feed MLAT to both piaware as well as adsb exchange, I would suggest to remove “–results beast,connect,localhost:30104” from one of the startup scripts which is either calling mlat-client or fa-mlat-client.


#8

Thanks; I had found this, already. Not knowing anything about the various bits of software and how they interact was a bit of a challenge, but I dug through the various directories, and googled some of the commands I found that seemed appropriate to the issue – leading to this same conclusion. I implemented this, rebooted, and no more noisy tracks.

Is there a reference someplace that outlines the setup? I see many references to very specific changes/adjustments, but no “view from 30,000 feet” description of things.


#9

I have in use one RasPi 2 + FA ProStick (the orange one) + FA 1090 MHz Filter and one RasPi 3 + FA ProStickPlus (the blue one).
On both installed dump1090 mutability v1.15 and PiAware (Debian Package Add-on) 3.3.0 , but I observe this “noise” (or ‘spreads’) only on my RasPi 2 and almost only when a Boeing RC-135 is in range (shown as MLAT) , but only sometimes.
On my RasPi 3 everythings looks ‘normal’.

Next I will connect the blue ProStick to RasPi 2 and the orange ProStick+Filter to RasPi 3 and will see what will happen …


#10

Hello. Do you have any instructions for how to do this? I’m having the same issue but haven’t been able to figure out how to fix it. Thanks!


#11

With the blue ProStickPlus at my R2 it’s still the same; sometimes “noise” in MLAT tracks …
On my R2 I still use dump1090-mutability v1.15~dev (the “old” one with google maps); on my R3 runs dump1090-mutability v1.15~dev (the “new” one with open street maps).
May be, the “old” version causes the “noise” …