[time-nuts] nuts about position

Joseph Gwinn joegwinn at comcast.net
Thu Apr 26 09:57:06 EDT 2018


On Wed, 25 Apr 2018 18:02:53 -0400, time-nuts-request at febo.com wrote:
> time-nuts Digest, Vol 165, Issue 50
> 
> Message: 3
> Date: Wed, 25 Apr 2018 10:19:38 -0500
> From: Dana Whitlow <k8yumdoober at gmail.com>
> To: Tom Van Baak <tvb at leapsecond.com>,  Discussion of precise time and
> 	frequency measurement <time-nuts at febo.com>
> Subject: Re: [time-nuts] nuts about position
> Message-ID:
> 	<CADHrwpdYA=fYzx+1S32NoK--wZiDK0G8kcA1Fpvky9O6uKtkHA at mail.gmail.com>
> Content-Type: text/plain; charset="UTF-8"
> 
> While I was at the Arecibo Observatory it became desirable to get a good
> surveyed position
> for a new GPS antenna we had installed for the NIST TMAS system.  We found
> a resource
> at the Univ of Puerto Rico who had a Trimble (I think) unit.  He set it up
> on the site, "turned on
> the bubble machine", then left it alone for about two hours.  He returned
> the estimated
> position a few days later, expressing high confidence that it was good
> within about 8 inches.
> 
> I'm sure I asked him if this machine used both L1 & L2, but don't recall
> his answer.   I suspect it was "yes".

It will have been using carrier phase only, not the L2 modulation 
(which is encrypted).  Although one can do correlation on the L2 
modulation from a given satellite in common view as well.

Joe Gwinn



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