Re: [gpsd-dev] [PATCH 1/3] TSIP: improve comments

[Hal Murray]

address@hidden said:
> >> > So what is the delay you see?  Can you identify your model and put
> >> > in the fudge you see automagically?  If not can you add in your
> >> > observed fudge as a comment? 

Don't fall into the trap of thinking that the offset is stable.  There are 
some/many devices where the offset is stable over a time scale of minutes but 
wanders with a time scale of hours.

Many of the SiRF chips have a peak-peak wander of 100 ms over a time scale of 
12 hours.

http://users.megapathdsl.net/~hmurray/ntp/GPSSiRF-off.gif

Yes, you can fudge out most of the error.  The point is watch for a day 
before concluding that you have the right answer.


-- 
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