[time-nuts] Time Transfer

[Bruce Griffiths]

Didier
Didier Juges wrote:
> Hi Brooke,
>
> Thank you for your suggestions, that page is probably ripe for a rewrite,
> but I may just add a link to your page for now :-)
>
> I would have thought the GPS receiver averages the readings when it locks on
> multiple satellites. Are you saying it only uses one at a time? If so,
> what's the point of a self survey?
>
>   
A weighted average is actually used as the measurement
quality/precision/accuracy varies from SV to SV due to geometry and
other factors.
Not one at a time (unless only one is visible) but the receivers with
less than 12 channels may not replace one of the 8 being tracked with a
"better" new candidate SV until one of the tracked SVs vanishes below
the horizon.
Only early GPS receivers tracked one SV at a time, swichting between
them periodically. Some carrier phase tracking receivers still do this
tracking each visible SV for a short while before switching to the next
in sequence.
> I talk about WWV because most ham operators have a receiver that receives
> WWV, so it is an inexpensive and convenient way to get an absolute
> reference, even though it is not as good as GPS.
>
> I am sure there is a reason why timing receivers track all the way down,
> instead of switching to a better bird when one is available, but by setting
> the mask angle fairly high (appropriate for your location and obstructions),
> you can take care of this problem.
>
> Didier KO4BB
>
>
>   
Bruce