Dear Bob, Sorry, the two plots are identical; it was a drag and drop fumble.
I should have given more detail - "tried many things" included running the receiver in position hold ( which is the default ) and free run. The receiver was being logged during operation and always claimed 5 to 10 SVs. The antenna is roof-mounted with an excellent view of the sky. I tried multiple antennas just in case, added a bit of gain, tried multiple SMT 360s, compared with other receivers in the lab ( Resolution T, Javad, Septentrio, VP Oncore) ... Another thing I didn't mention was that I tried it on a GPS simulator, except with a position in the Northern hemisphere ( I'm in the South ) and it worked fine for 12 hours. I wasn't sure what to make of this but decided to stop spending my time on this because it was really Somebody Else's Problem to solve. In the end, I decided to use another receiver for my application ( GPS common view, for which we'd been using the Resolution T previously ) but now that that's almost done, I thought I'd have another look at the the SMT 360 problems. Cheers Michael On Tuesday, 19 April 2016, Bob Camp <[email protected]> wrote: > Hi > > The two plots shown appear to be identical. If they are actually two > different > runs, the problem repeats very closely. > > If the GPS is not in position hold *and* the antenna is less than ideal - > That’s > the sort of thing you may see. Essentially it’s got two locations it > “thinks” are > correct. Another possibility is a position hold situation with a very low > satellite count. > As a single observed satellite goes in and out of multi path, the solution > goes all over the place. > Again, you need a challenged antenna for this to happen. Pretty much all > of this > would be apparent from the normal messages out of the part. > > Bob > > > > > On Apr 18, 2016, at 10:13 PM, Michael Wouters <[email protected] > <javascript:;>> wrote: > > > > Does anyone have experience with the Trimble SMT 360 ? > > > > I bought some of these four or five months after they were released. > During > > testing, the 1 pps output evidenced a problem, as shown in the attached > > plot (the 1 pps is being measured against a Cs beam standard), which is > > not sawtooth-corrected. While there are longish periods of nominal > > operation, the receiver seems to hop between two solutions. This > behaviour > > is well out of specification. > > > > When I contacted Trimble support, they said that the firmware in the > > receivers was very early, and replaced the receivers. However, the > problem > > was still evident with the new firmware. Trimble did not respond to > further > > emails. > > > > I tried many things to isolate the problem, including restricting the > > receiver to GPS-only but I was unable to make an improvement. > > > > I would like to know if anyone else is operating an SMT 360 and if they > > have seen any similar behaviour. > > > > Cheers[image: Inline image 2] > > Michael[image: Inline image 1] > > <smt360.png><smt360.png>_______________________________________________ > > time-nuts mailing list -- [email protected] <javascript:;> > > To unsubscribe, go to > https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > > and follow the instructions there. > > _______________________________________________ > time-nuts mailing list -- [email protected] <javascript:;> > To unsubscribe, go to > https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. > _______________________________________________ time-nuts mailing list -- [email protected] To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
