[time-nuts] Timing or Navigation GPS Receivers (was: Turning off PPS when not enough satellites)
Ulrich Bangert
df6jb at ulrich-bangert.de
Wed Aug 2 13:42:57 EDT 2006
Hi Brooke,
thank you for the links! I wish one would explain this method to me and
the rest of the newsgroup in the speak typical for time nuts. Is it
really something that I can do in reality? What is the cost of the
Ashtech receiver? Why is this method un-discussed here?
Best regards
Ulrich Bangert
> -----Ursprüngliche Nachricht-----
> Von: time-nuts-bounces at febo.com
> [mailto:time-nuts-bounces at febo.com] Im Auftrag von Brooke Clarke
> Gesendet: Dienstag, 1. August 2006 21:50
> An: Discussion of precise time and frequency measurement
> Betreff: [time-nuts] Timing or Navigation GPS Receivers (was:
> Turning off PPS when not enough satellites)
>
>
> Hi Ulrich:
>
> It's interesting that the now in development carrier phase GPS time
> transfer method that might offer 1,000 times lower
> uncertanity is based
> on the Ashtech Z12 surveying receiver, not a timing specific
> GPS receiver.
> http://scholar.google.com/scholar?q=Ashtech%20Z12%20carrier%20
> phase%20GPS%20time%20transfer&hl=en&lr=&oi=scholart
>
> Have Fun,
>
> Brooke Clarke
>
> --
> w/Java http://www.PRC68.com
> w/o Java http://www.pacificsites.com/~brooke/PRC68COM.shtml
> http://www.precisionclock.com
>
>
>
> Ulrich Bangert wrote:
>
> >Poul-Henning did already give the answer. However i am not
> very happy
> >with the formulation
> >
> >
> >
> >>In other words, it has nothing to do with the receiver, it's
> >>about what you ask it to do.
> >>
> >>
> >
> >because
> >
> >a) I never saw a navigation receiver featuring a "position hold" mode
> >
> >b) I never saw a timing receiver featuring a "navigate
> forever" mode.
> >Everything that i had in my hands had a "automatic site survey" mode
> >after which it would return to "position hold". That's why i
> think the
> >formulation that it depends on the receiver's primary purpose is not
> >that wrong!
> >
> >Regards
> >Ulrich Bangert
> >
> >
> >
> >>-----Ursprüngliche Nachricht-----
> >>Von: time-nuts-bounces at febo.com
> >>[mailto:time-nuts-bounces at febo.com] Im Auftrag von Poul-Henning Kamp
> >>Gesendet: Dienstag, 1. August 2006 12:28
> >>An: bg at lysator.liu.se; Discussion of precise time and
> >>frequency measurement
> >>Betreff: Re: [time-nuts] Turning off PPS when not enough satellites
> >>
> >>
> >>In message
> >><63849.212.181.149.145.1154423937.squirrel at webmail.lysator.liu.se>,
> >>bg at lysator.liu.se writes:
> >>
> >>
> >>>On Tue, August 1, 2006 10:56, Ulrich Bangert said:
> >>>
> >>>
> >>>
> >>>>Note that any gps receiver can not be really good for timing and
> >>>>navigation at the same time, so all navigation
> >>>>
> >>>>
> >>receivers
> >>
> >>
> >>>>make bad timing receivers.
> >>>>
> >>>>
> >>>I am interested in your arguments for the above statement. Please
> >>>elaborate!
> >>>
> >>>
> >>The above statement should probably be read as:
> >>
> >>"If you solve for both position and time you get worse time
> >>than if you hold the position constant and solve only for time"
> >>
> >>In other words, it has nothing to do with the receiver, it's
> >>about what you ask it to do.
> >>
> >>Not all receivers can do "position hold" mode of course.
> >>
> >>--
> >>Poul-Henning Kamp | UNIX since Zilog Zeus 3.20
> >>phk at FreeBSD.ORG | TCP/IP since RFC 956
> >>FreeBSD committer | BSD since 4.3-tahoe
> >>Never attribute to malice what can adequately be explained by
> >>incompetence.
> >>
> >>
>
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