From aen@haystack.mit.edu Fri Aug 24 10:03:19 EDT 2001
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From: arthur_niell
Message-Id: <200108241403.KAA24464@newton.haystack.edu>
Subject: RE: Z-Surveyor and external freq ref (fwd)
To: Frank.E.Marion@noaa.gov
Date: Fri, 24 Aug 2001 10:03:33 EDT
Cc: map@newton.haystack.edu, miranda@tango.grdl.noaa.gov (Miranda Chin),
linda@lynx.grdl.noaa.gov (Linda Nussear),
jimr@maia.usno.navy.mil (Jim Ray)
X-Mailer: Elm [revision: 109.18]
Status: RO
Ernie,
I asked Robert Snow of Ashtech for his version of locking the Z-Surveyor
to an external reference (I'm sorry if this duplicates your efforts), and
here is his reply. Please let me know if this is different from what you
have done. If it is, please try it, then we can see if it improves the
time stability of the WES2 system.
Could you let me know which version of the firmware is being used?
Thanks.
-arthur
------------------------------------------------------------------------
> Hi Arthur,
>
> The general procedure to use a 5 MHz external oscillator is to connect the
> source, then issue the command $PASHS,EXT,5,A. This will force the receiver
> to use the external 5 MHz frequency and to automatically switch to internal
> if the external clock fails. (You can use an N instead of an A if you want
> the receiver to stop tracking if the external frequency fails).
>
> You must also turn off clock steering by sending the command $PASHS,UTS,N.
> If clock steering is on it may corrupt the results.
>
> Please let me know if this works, and if not which firmware version is in
> use.
>
> Best Regards,
>
> Robert
>
> ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
>
> Magellan is now a proud part of THALES NAVIGATION
>
> ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> Dr. Robert Snow
> Director of Reference Station Sales
> THALES NAVIGATION
> 471 El Camino Real, Santa Clara, CA 95050, USA
> Tel: +1 (408) 615-5246 Fax: +1(408) 615-5200
> Mobile: +1 (650) 576-6611
>
> e-mail: rsnow@magellangps.com
>
>
> ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
>
> connect the source, then
>
> -----Original Message-----
> From: arthur_niell [mailto:aen@haystack.mit.edu]
> Sent: Thursday, August 23, 2001 11:59 AM
> To: rsnow@magellangps.com
> Cc: miranda@tango.grdl.noaa.gov; jimr@maia.usno.navy.mil;
> aen@dopey.haystack.edu
> Subject: Z-Surveyor and external freq ref
>
>
> Hi Robert,
>
> Due to a dearth of receivers, NOAA has installed an Ashtech Z-Surveyor
> at Westford following the loss of the last receiver to lightning. The
> Z-Surveyor receiver is supposed to be referenced to the Hydrogen maser 5
> MHz, and from internal checks it appears to be (see note below from
> Ernie Marion at NOAA; also I talked to Miranda Chin at NOAA who looked
> at the TEQC output and says it appears okay). However, the clock still
> is varying by 50 ns pk-to-pk (diurnally) with respect to the USNO GPS
> combined time and so does not appear to be locked to the maser, which
> keeps time to about a nanosec in terms of diurnal signals. Are there
> special setup procedures to get the Z-Surveyor to lock to the 5 MHz?
>
> -arthur
>
>
> ----------------------------------------------------------------
> Dr. Arthur Niell aniell@haystack.mit.edu
> MIT Haystack Observatory 1-781-981-5416 office
> Westford, MA 01886 1-978-692-4764 receptionist
> 1-781-981-0590 FAX
> ----------------------------------------------------------------
>
> > Mike,
> >
> > I checked out the receiver and it tells me its using the 05.00MHz
> > external clock - Miranda also check the TEQC output and found everything
> > OK - Please have Aurther contact Miranda for more information if needed
> >
> > -Ernie
> >
> >
> >
> >
From Frank.E.Marion@noaa.gov Fri Aug 24 11:58:08 EDT 2001
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From: Frank Marion
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To: arthur_niell
CC: map@newton.haystack.edu, Miranda Chin ,
Linda Nussear ,
Jim Ray
Subject: Re: Z-Surveyor and external freq ref (fwd)
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Status: RO
Arthur,
The receiver's firmware ver. is ZB00 - also I was not told by Ashtech's Tech Support to "turn off
clock steering" before issuing the command to use the external clock - I have now given both commands
to the receiver, so lets see how things look after about 16:00 utc
-Ernie
arthur_niell wrote:
> Ernie,
>
> I asked Robert Snow of Ashtech for his version of locking the Z-Surveyor
> to an external reference (I'm sorry if this duplicates your efforts), and
> here is his reply. Please let me know if this is different from what you
> have done. If it is, please try it, then we can see if it improves the
> time stability of the WES2 system.
>
> Could you let me know which version of the firmware is being used?
>
> Thanks.
>
> -arthur
>