Re: [time-nuts] How to achieve best results from U-Blox survey-in
Hi SBAS is normally turned off for timing because historically it was not optimized for timing use. The “try it and see” approach tended to show it caused more trouble in a timing application than it fixed. For survey on an L1 device, it is a good idea to use it. Bob > On May 8, 2016, at 4:32 PM, Pete Stephenson wrote: > > On Sun, May 8, 2016 at 7:25 PM, Bob Stewart wrote: >> Yes, disable all except GPS sats. Also, turn off SBAS, set your max and min >> number of sats (defaults are probably what you want), and the satellite >> elevation mask. The elevation mask defaults to 5, but can you really see >> that low? > > Hi Bob, > > Out of curiosity, why would one turn off SBAS? My first instinct is > that SBAS support could only improve the accuracy of one's fix, as it > supplies additional correction information that improves on the normal > GPS signal. I would (perhaps naively) think that enabling SBAS during > the surveying would improve the results. > > Of course, I could very well be mistaken and would be happy to be > corrected by those more knowledgeable. > > Cheers! > -Pete > > -- > Pete Stephenson > ___ > 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.
Re: [time-nuts] How to achieve best results from U-Blox survey-in
Hi Pete, >From Bob Camp's comments, I think you're right. I hadn't considered survey as >an issue by itself. I've only been concerned about timing, and one of the >Ublox manuals says to turn off SBAS for timing applications. Bob On Sun, 5/8/16, Pete Stephenson wrote: Subject: Re: [time-nuts] How to achieve best results from U-Blox survey-in To: "Discussion of precise time and frequency measurement" Date: Sunday, May 8, 2016, 3:32 PM On Sun, May 8, 2016 at 7:25 PM, Bob Stewart wrote: > Yes, disable all except GPS sats. Also, turn off SBAS, set your max and min number of sats (defaults are probably what you want), and the satellite elevation mask. The elevation mask defaults to 5, but can you really see that low? Hi Bob, Out of curiosity, why would one turn off SBAS? My first instinct is that SBAS support could only improve the accuracy of one's fix, as it supplies additional correction information that improves on the normal GPS signal. I would (perhaps naively) think that enabling SBAS during the surveying would improve the results. Of course, I could very well be mistaken and would be happy to be corrected by those more knowledgeable. Cheers! -Pete -- Pete Stephenson ___ 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.
Re: [time-nuts] How to achieve best results from U-Blox survey-in
On Sun, May 8, 2016 at 7:25 PM, Bob Stewart wrote: > Yes, disable all except GPS sats. Also, turn off SBAS, set your max and min > number of sats (defaults are probably what you want), and the satellite > elevation mask. The elevation mask defaults to 5, but can you really see > that low? Hi Bob, Out of curiosity, why would one turn off SBAS? My first instinct is that SBAS support could only improve the accuracy of one's fix, as it supplies additional correction information that improves on the normal GPS signal. I would (perhaps naively) think that enabling SBAS during the surveying would improve the results. Of course, I could very well be mistaken and would be happy to be corrected by those more knowledgeable. Cheers! -Pete -- Pete Stephenson ___ 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.
Re: [time-nuts] How to achieve best results from U-Blox survey-in
Hi For *survey* I would leave SBAS turned on. I would also suggest that something like a 3 to 5 day run is needed. That’s way beyond what the firmware can analyze. You at least need something like LH to capture and analyze data. Since LH does not run on the uBlox, that sets you back to serial capture and playing with things like .cvs files. Bob > On May 8, 2016, at 1:25 PM, Bob Stewart wrote: > > Hi Neil, > > Yes, disable all except GPS sats. Also, turn off SBAS, set your max and min > number of sats (defaults are probably what you want), and the satellite > elevation mask. The elevation mask defaults to 5, but can you really see > that low? > > There are different ideas about how long to run the survey. On the one hand, > these new receivers get a good position pretty quickly. On the other, if you > wait 24 hours, you get the benefit of having that many measurements figure > into the result. Don't forget that the antenna placement can make or break a > timing system. I've been struggling along with my antenna placed just under > the eave on a south facing window, but finally got one put in a clear > position on top of the house. It does make a difference. > > Bob > > On Sun, 5/8/16, Neil Green wrote: > > Subject: [time-nuts] How to achieve best results from U-Blox survey-in > To: "Discussion of precise time and frequency measurement" > > Date: Sunday, May 8, 2016, 11:18 AM > > I have a U-Blox LEA-M8F eval module > from CSG Shop and want to run a survey-in. Are there any > “best practices” for doing this, e.g. using just GPS and > disabling GLONASS et al? Any tips are much appreciated. > ___ > 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.
Re: [time-nuts] How to achieve best results from U-Blox survey-in
Hi Neil, Yes, disable all except GPS sats. Also, turn off SBAS, set your max and min number of sats (defaults are probably what you want), and the satellite elevation mask. The elevation mask defaults to 5, but can you really see that low? There are different ideas about how long to run the survey. On the one hand, these new receivers get a good position pretty quickly. On the other, if you wait 24 hours, you get the benefit of having that many measurements figure into the result. Don't forget that the antenna placement can make or break a timing system. I've been struggling along with my antenna placed just under the eave on a south facing window, but finally got one put in a clear position on top of the house. It does make a difference. Bob On Sun, 5/8/16, Neil Green wrote: Subject: [time-nuts] How to achieve best results from U-Blox survey-in To: "Discussion of precise time and frequency measurement" Date: Sunday, May 8, 2016, 11:18 AM I have a U-Blox LEA-M8F eval module from CSG Shop and want to run a survey-in. Are there any “best practices” for doing this, e.g. using just GPS and disabling GLONASS et al? Any tips are much appreciated. ___ 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.
