HI > On Apr 7, 2016, at 10:43 AM, Björn <b...@lysator.liu.se> wrote: > > For navigation more measurements have always been prefered - that is use as > many GNSS systems as all your receicers support.
I agree that should be correct in principle. My observation of the modules on the market today is that each constellation tends to create it’s own antenna location. If you try to blindly merge them all together, the result is not an improvement over the long term solution from a single system. If you are doing corrected measurements, this would not apply. The survey in process on a GPSDO is generally a blind process rather than a corrected process. > > That should be true also for common view timing. Common view, (where things are corrected) quite possibly. For the type of timing a basement GPSDO does, you have the same “each constellation has it’s own time” problem. Bob > > -- > Björn > > <div>-------- Originalmeddelande --------</div><div>Från: Bob Camp > <kb...@n1k.org> </div><div>Datum:2016-04-07 18:41 (GMT+07:00) > </div><div>Till: Bob Stewart <b...@evoria.net>, Discussion of precise time > and frequency measurement <time-nuts@febo.com> </div><div>Rubrik: Re: > [time-nuts] LEA-M8T </div><div> > </div>Hi > > Indeed, if you have not turned off the other systems for timing, you will > have issues. Even for > precision navigation, you need to turn them off. Until the European system > goes up, there will > not ba a coordinated approach between any two of the systems. Right now they > each make their > own assumptions and their own definitions. If you are driving a car down the > road, that’s not a > big deal. If you are trying to do TimeNuts stuff … A one meter delta is a big > deal for timing. A “few” > nanoseconds (say >10) is also a big deal. > > Bob > > >> On Apr 6, 2016, at 9:39 PM, Bob Stewart <b...@evoria.net> wrote: >> >> Hi Logan, >> >> I seem to remember Bob Camp mentioning that you can't have multiple >> satellite sources in the mix, because the other satellites are inferior to >> the GPS sats in timing. Maybe Bob or someone could address this. I would >> love to discover that I've set something wrong in all the many, many data >> structures. >> >> Bob >> >> >> -------------------------------------------- >> On Wed, 4/6/16, Logan Cummings <logan.cummi...@gmail.com> wrote: >> >> Subject: Re: [time-nuts] LEA-M8T >> To: "Bob Stewart" <b...@evoria.net>, "Discussion of precise time and >> frequency measurement" <time-nuts@febo.com> >> Date: Wednesday, April 6, 2016, 8:18 PM >> >> Hi >> Bob, >> Can't speak to >> jitter accuracy but the M8 series is definitely not the same >> receiver in the 6 series. As you probably know, M8 >> introduced multi-GNSS support so in addition to GPS you have >> Beidou and Glonass satellites. >> At work we've had some gnashing of >> teeth about the wider filter passband requirements for >> multi-GNSS support since we're operating in a noisy >> environment, but I have nothing further on degraded >> performance when using only GPS. >> Would be interesting to let >> it have all the constellations and see what >> happens. >> -Logan >> On Wed, Apr 6, 2016 at >> 10:04 AM, Bob Stewart <b...@evoria.net> >> wrote: >> I >> recently bought a number of LEA-M8T receivers and I have to >> say that I am unimpressed, so far. They don't survey >> to the same reported accuracy as the LEA-6T in the same >> amount of time. They certainly aren't better in the >> jitter after sawtooth correction. So, have I managed to >> overlook some new field, or are they just not the same >> receiver as the 6T? I did shut all sats off except GPS >> sats. >> >> >> >> Bob - AE6RV >> >> _______________________________________________ >> >> time-nuts mailing list -- time-nuts@febo.com >> >> To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts >> >> and follow the instructions there. >> >> >> _______________________________________________ >> time-nuts mailing list -- time-nuts@febo.com >> To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts >> and follow the instructions there. > > _______________________________________________ > time-nuts mailing list -- time-nuts@febo.com > To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. > _______________________________________________ > time-nuts mailing list -- time-nuts@febo.com > To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. _______________________________________________ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
