[ntp:questions] Re: PPS SYNC DISABLED
david at djwhome.demon.co.uk
Sat Aug 12 13:48:05 UTC 2006
In article <1155356115.545749.124090 at h48g2000cwc.googlegroups.com>,
Eugen COCA <ecoca at eed.usv.ro> wrote:
> Thomas Laus wrote:
> > It should happen twice a day, nearly 12 hours apart. Each GPS satellite
> > is in an approx. 12 hour orbit. Your view of the constellation is the
> > same about every 12 hours.
> hours. But, in a fixed point on the Earth, a receiver do not see one
> satellite for 12 hours ! And, the algorithm implemented in the receiver
He never said that one satellite was seen for 12 hours. Or at least
not in the quoted bit.
> select the strongest signal from those received one time. So, the
> receiver locks on several satellites over a day.
A non-site surveyed receiver needs at least four satellite before it can
even solve for time and should use all of those in view to reduce the
A site surveyed receiver could use one satellite, but ought to use all of
those in view. Signal strength is not a good measure of which is the
(As a pedantic point, for any one satellite there will be points on the
earth that see it for a complete orbit.)
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