On Wed, 25 Apr 2018 18:02:53 -0400, time-nuts-request@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@gmail.com> > To: Tom Van Baak <tvb@leapsecond.com>, Discussion of precise time and > frequency measurement <time-nuts@febo.com> > Subject: Re: [time-nuts] nuts about position > Message-ID: > <CADHrwpdYA=fYzx+1S32NoK--wZiDK0G8kcA1Fpvky9O6uKtkHA@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