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generating an accurate antenna height measurement due to the way GPS works. 
They  don't seem to have a problem generating good long/lat coordinates. But in  
timing, all three axis need to be precise unfortunately.
 
bye,
Said
 
 
In a message dated 1/6/2009 03:23:53 Pacific Standard Time,  
pvince at theiet.org writes:

Said  wrote:

>When we say units typically have 25ns unit-to-unit variation  on the 1PPS on 
 
>un-calibrated units, then I believe most of this  is caused by the 
auto-survey  
>position errors of the GPS  receiver. One could get much better performance 
by 
> manually entering  the exact position-hold position of the antenna, and 
then   
>calibrating for antenna cable delay (in 1ns steps).

A naive  question, if I may: how do I go about doing a precise manual 
position survey?  Is it simply a case of letting the unit self 
survey, then manually  entering different co-ordinates (say +/- 10 metres) in 
each of the three  directions in turn, watch the 
signal output, and try to tune for minimum  wobble?

Thanks,   Peter