[time-nuts] More Comments on GPS's ADEV

Hal Murray hmurray at megapathdsl.net
Wed Apr 11 01:20:38 EDT 2007


> FYI -- Note that between 10,000 and 100,000 seconds, the uncalibrated
> diurnal ionosphere signature just about doubles the noise level. The
> GPS broadcast signals contain an approximate ionosphere correction
> that is based on sunspot count, and most receivers follow the GPS
> ICD200 "recipe". However, this "cookbook" correction makes no attempt
> to calibrate for day/night variations, or the variation of the
> ionosphere with latitude. This typically gives rise to a diurnal clock
> signal that is 10-20 nsec in size. 

Neat.  Thanks.

Is there a corresponding position shift between day and night?  Which 
direction?

Could I get better results if I ran the typical survey step twice, once 
during the day and again at night, and swapped between them at sunset and 
sunrise?




-- 
These are my opinions, not necessarily my employer's.  I hate spam.







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