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 Post subject: "Noise" in MLAT tracks after upgrading to Pi 3
PostPosted: Wed Mar 08, 2017 8:21 am 
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ToyonADSB - FlightAware user avatar

Joined: Tue Feb 21, 2017 10:27 pm
Posts: 17
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

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

Did I do something to screw up the timing?

Thanks!


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 Post subject: Re: "Noise" in MLAT tracks after upgrading to Pi 3
PostPosted: Wed Mar 08, 2017 8:31 am 
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FlightAware Staff
obj - FlightAware user avatar

Joined: Tue Sep 30, 2014 7:14 pm
Posts: 3193
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.


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 Post subject: Re: "Noise" in MLAT tracks after upgrading to Pi 3
PostPosted: Wed Mar 08, 2017 9:33 am 
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ToyonADSB - FlightAware user avatar

Joined: Tue Feb 21, 2017 10:27 pm
Posts: 17
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!


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 Post subject: Re: "Noise" in MLAT tracks after upgrading to Pi 3
PostPosted: Wed Mar 08, 2017 10:06 am 
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FlightAware Staff
obj - FlightAware user avatar

Joined: Tue Sep 30, 2014 7:14 pm
Posts: 3193
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.


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 Post subject: Re: "Noise" in MLAT tracks after upgrading to Pi 3
PostPosted: Wed Mar 08, 2017 10:23 am 
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ToyonADSB - FlightAware user avatar

Joined: Tue Feb 21, 2017 10:27 pm
Posts: 17
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).


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 Post subject: Re: "Noise" in MLAT tracks after upgrading to Pi 3
PostPosted: Wed Mar 08, 2017 10:38 am 
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FlightAware Staff
obj - FlightAware user avatar

Joined: Tue Sep 30, 2014 7:14 pm
Posts: 3193
I don't know what their setup scripts do; you'd need to ask how to disable their stuff on their forums.


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 Post subject: Re: "Noise" in MLAT tracks after upgrading to Pi 3
PostPosted: Wed Mar 08, 2017 3:12 pm 
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jluebbe - FlightAware user avatar

Joined: Mon Dec 12, 2016 12:26 pm
Posts: 5
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.


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 Post subject: Re: "Noise" in MLAT tracks after upgrading to Pi 3
PostPosted: Wed Mar 08, 2017 7:27 pm 
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ToyonADSB - FlightAware user avatar

Joined: Tue Feb 21, 2017 10:27 pm
Posts: 17
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.


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 Post subject: Re: "Noise" in MLAT tracks after upgrading to Pi 3
PostPosted: Thu Mar 09, 2017 2:52 pm 
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infomb - FlightAware user avatar

Joined: Wed Mar 16, 2016 9:54 am
Posts: 14
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 ...


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