[time-nuts] Position accuracy and Thunderbolt performance

[GandalfG8 at aol.com]

In a message dated 26/07/2009 17:09:06 GMT Daylight Time,  
holrum at hotmail.com writes:

I did a  rather interesting test on the effects of the survey position 
accuracy on the  Thunderbolt.  Attached are two plots.  The first one is with 
the  Tbolt position within three feet of the actual location.  The second show 
 the results when the Tbolt is told it is 200 feet from where it actually  
is.  

The graphs are scaled to the same scale factors.  The  jumps in the 200 
foot graph are NOT correlated to satellite constellation  changes, etc.  The 
self-reported performance is degraded by a factor of  around 10.  

The quantization and structure of the 200 foot graph  is totally 
unexpected.  It may help explain things like the DAC spikes in  divisions 5 and 7 of 
the 3foot.gif graph.



------------------
That's certainly a significant difference, but would you expect that under  
more normal circumstances?
 
Or. to put it another way, what could we reasonably  expect to see as a 
position error if the T'bolt is  allowed to self survey?
 
regards
 
Nigel
GM8PZR