AirNav Systems Forum
AirNav RadarBox and RadarBox24.com => AirNav RadarBox and RadarBox24.com Discussion => Topic started by: DaveReid on February 27, 2010, 11:10:16 AM
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In the course of developing ADS-B decoding software for a client, I've been looking at the RadarBox position decoding bug that affects some ATPs and assorted other aircraft.
I'm close to formulating a theory re the nature of the bug, which will hopefully lead to a fix that AirNav can implement, but in the meantime it would be helpful to know if anyone has seen spurious position data for any of the following other aircraft:
43E7DD M-SPEC B350
A0055E N100GV GLF5
A00986 N101MH GLF5
AE0876 01-0025 GLF5
MTIA
Dave
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Hi Dave,
I have whacky positional data for the first three. No record of the last one. Let me know if you'd like details.
Cheers
Victor
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I have whacky positional data for the first three. No record of the last one. Let me know if you'd like details.
Thanks. Simply the fact that you're able to confirm my suspicions is a great help.
AirNav: I would strongly question the wisdom of displaying decoded coordinates where the NUC_P is 3 and the CPR encoded longitude is all zeroes - that's what the invalid packets from the above aircraft appear to have in common.
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The tech details actually mean little to me (well nothing actually!), but it sounds like you have had an Eureka moment ! Well done.
Airnav - Would your techs like to comment ? I know the spikes on the polar diagram aren't a big concern to most, but I must admit I find them rather irksome. It would be good if they could be despatched ?
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Airnav - Is there any comment from your side on this subject ?
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It is being investigated and details have been passed to our development team.
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I'm expecting them to hire me any day now :-)
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Thanks for your response Airnav.
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I'm expecting them to hire me any day now :-)
(http://i454.photobucket.com/albums/qq269/Thebsrman/pigscannotfly1.jpg)
From pat
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I'm expecting them to hire me any day now :-)
(http://i454.photobucket.com/albums/qq269/Thebsrman/pigscannotfly1.jpg)
From pat
Very Good Pat,LOL.
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Add N93M to the list Dave another GLF5 showing 1493nm from centre of england at 16.15 today.
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Add N93M to the list Dave another GLF5 showing 1493nm from centre of england at 16.15 today.
Thanks for the heads-up, just in time to get the packet analyser on this one !
Same thing seems to apply as before: spurious DF17 AP squitters with NUC_P = 3 and the CPR encoded longitude all zeroes.
Not that I had any acknowledgement from AirNav following my original post - I think I'll stop trying to be helpful :-)
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Dave - going back a long way - maybe a year - I recall that my first long distance bizarre positions were all USA reg. Gulfstreams. At the time I ascribed those to deliberate obfuscation of their positions for reasons one can only surmise.
That may well be rubbish but it certainly seems to be a predominantly Gulfstream phenomenon.
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Ref reply#10
He must have been really shifting, - just west of me at 1635 :-)
Syd
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Dave - going back a long way - maybe a year - I recall that my first long distance bizarre positions were all USA reg. Gulfstreams. At the time I ascribed those to deliberate obfuscation of their positions for reasons one can only surmise.
That may well be rubbish but it certainly seems to be a predominantly Gulfstream phenomenon.
I don't think it's deliberate, if only because it's dead easy to filter out the erroneous position transmissions, leaving the good ones. But I would certainly agree that GLF5s seem to be the main culprits.
This is eerily similar to a bug in BaseStation a few years ago where spurious positions were being shown, mostly for Canadair Challenger aircraft.
The bug was subsequently fixed by Kinetic - I didn't have a packet monitor in those days, so I don't know the exact details, only the symptoms.
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But I would certainly agree that GLF5s seem to be the main culprits.
Captured this one over Sydney a while ago. (click to enlarge)
(http://img151.imageshack.us/img151/2717/wtf2i.jpg) (http://img151.imageshack.us/img151/2717/wtf2i.jpg)
(http://img151.imageshack.us/img151/9549/wtf1a.jpg) (http://img151.imageshack.us/img151/9549/wtf1a.jpg)
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Gulf5 id SAM special air mission @ 7448 nm time 10.42 today
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AirNav - Can you confirm this issue will (or will not) be put on the bug list ?
http://www.airnavsystems.com/bugs/
Thanks
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Another oddment @ 1505 hrs today SE-MAJ callsign WLX900 at 1726 nm from central england.
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Another oddment @ 1505 hrs today SE-MAJ callsign WLX900 at 1726 nm from central england.
British Aerospace ATP - say no more :-)
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ATP?
J.
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Yes, ATP.
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British Aerospace ATP - say no more :-)
Just managed to take my first 3D screenshot of a BAe ATP behaving properly.
Shame no model or livery available yet, but nice to see it climbing out over Warwickshire with correct transmissions!
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I am sorry. I am being nieve and I just thought a non-sarcastic answer would help. ATP? 73 de J.
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I am sorry. I am being nieve and I just thought a non-sarcastic answer would help. ATP? 73 de J.
Well it would help if we understood what it is that you want to know. Simply posting "ATP?" would suggest that you wanted confirmation of what you've already been told :-)
Are you asking what an ATP is ?
www.google.co.uk/#hl=en&q=ATP+aircraft
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I am sorry. I am being nieve and I just thought a non-sarcastic answer would help. ATP? 73 de J.
Well it would help if we understood what it is that you want to know. Simply posting "ATP?" would suggest that you wanted confirmation of what you've already been told :-)
Are you asking what an ATP is ?
www.google.co.uk/#hl=en&q=ATP+aircraft
DR,
Thank you.
Oh come on!!!!!
J.
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I give up, then.