Aircraft with positions that jump - some diagnostics

[tarbat]

Like others, I occasionally see an aircraft with position jumping by thousands of miles (aka purple rain).  Today, I had an aircraft doing this very close to my home, and was able to observe a couple of things that might help diagnose what's going wrong:

1. The aircraft was close to my home, so the problem is unlikely to be caused by poor signal from the aircraft or interference from other signals.

2. I noticed that when the aircraft timed-out, the purple rain dissapeared, even though the rest of the trail remained on screen.  Even the trail BEFORE the purple rain remained on screen.

BTW, the aircraft was A1F3FD, reg: N225EE, a Gulfstream Aerospace G-V Gulfstream V.

[RodBearden]

I've certainly had a recent Gulfstream close to home distributing purple rain like is was going out of fashion.

Is there something about Gulfstreams?

Rod

[DaveReid]

Is there something about Gulfstreams?

That's entirely possible. 

It's reminiscent of a (now fixed) bug in BaseStation which affected Challengers and resulted in spurious positions being displayed - the fix was a firmware upgrade.  Don't ask me to explain why and how the bug was restricted to one aircraft type - I don't know - but we could be seeing a parallel here.

[Falcon]

Hello,

I had an aircraft jumping around a couple of days ago and again this morning. I've actually had it occur a number of times and was going to get in touch with support about it, and the purple lines that are displayed right across my screen at certain times. While the solid purple lines that extend right across the screen can be created when an aircraft does this may not be an appropriate reaction by the RB software when it encounters a bad transponder, I did manage to confirm with another person who tracks aircraft using lets say another brand of tracking device to confirm that the same aircraft that I had observed jumping around was also doing the same on his display (no purple lines though). At least I now know one cause for the purple lines in the RB software.

[jgrloit]

I am not sure if this is the same problem, but I have had an aircraft whose position when decoded is wrong by between 4 and 8 degrees of Latitude
The resulting position is around 50 degrees latitude, which is far outside my viewing area.
The latest occurrance was over night this morning, and is not listed in mylog views, so I suspect that the position was not either the starting or ending one.