Time Nutters-- Mark Sims said of the latest release of Lady Heather: > There are several cosmetic tweaks. A major new feature is the ability to write RINEX files for receivers that can output satellite RAW observation data. RINEX files can be processed to produce very accurate positions (typically 150-250mm for L1 only receivers, 10mm for L1/L2 receivers). The recommended online processor is CSRS-PPP from Natural Resources of Canada (NARCAN)... they seem to be the only service that supports L1 only data. ************ In layman's terms, what does this mean with regard to being able to set an *AFFORDABLE* GPS RX out in the field and use it to do site surveys and process the recorded RINEX data later to establish the geo-position of each of the sites within a precision of +/- a few centimeters? I presume this may not be a simple as setting up my Trimble Thunderbolt and Lady Heather V6.0 in the field and gathering RINEX files for a few minutes....?? Mike Baker Micanopy, FL *************

Hi > On Jul 2, 2018, at 6:49 PM, Michael Baker <mpb45@clanbaker.org> wrote: > > Time Nutters-- > > Mark Sims said of the latest release of Lady Heather: > >> There are several cosmetic tweaks. > > A major new feature is the ability to write RINEX files for receivers that can output satellite RAW observation data. RINEX files can be processed to produce very accurate positions (typically 150-250mm for L1 only receivers, 10mm for L1/L2 receivers). The recommended online processor is CSRS-PPP from Natural Resources of Canada (NARCAN)... they seem to be the only service that supports L1 only data. > ************ > > In layman's terms, what does this mean with regard to being > able to set an *AFFORDABLE* GPS RX out in the field and use it > to do site surveys and process the recorded RINEX data later to > establish the geo-position of each of the sites within a precision > of +/- a few centimeters? I presume this may not be a simple as > setting up my Trimble Thunderbolt and Lady Heather V6.0 in the > field and gathering RINEX files for a few minutes....?? Even with L1/L2 survey gear, “a few centimeters” is a bit more than a few minutes of data. So far, 24 hour records with L1 gear have given meter level precision. Bob > > Mike Baker > Micanopy, FL > ************* > > > _______________________________________________ > time-nuts mailing list -- time-nuts@lists.febo.com > To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com > and follow the instructions there.

I've done some experiments with the NV08C and NEO8MT recently. Both of these receivers report L1 carrier phase. Using the CSRS-PPP service, I don't get quite as good results as Mark. The errors are more like 0.5 m (95% confidence interval) in X,Y,Z. However, there is a systematic error too of about 0.5 m, mostly in Z. My guess is that it's because I'm in Australia and CSRS don't have as much data as they do in North America for estimating ionosphere. There is a dense local CORS network but access is not free. The other thing I tried was using the receivers in base-rover configuration with various CORS stations out to 100 km and this worked very well. The positions I got using RTKLIB were good to 5 cm or so. I know exactly where the antenna is because it's an IGS station. The NV08 worked best. Antenna quality was important too. When I moved from the choke ring to a 'cheap and cheerful' there was a marked decrease in the quality of the data - the RTKLIB positioning solution would drop in and out of lock. Nonetheless, useable data could be obtained. Other things I have read suggest that this could be improved with more sophisticated software. Cheers Michael On Wed, 4 Jul 2018 at 3:15 am, Bob kb8tq <kb8tq@n1k.org> wrote: > Hi > > > > > On Jul 2, 2018, at 6:49 PM, Michael Baker <mpb45@clanbaker.org> wrote: > > > > Time Nutters-- > > > > Mark Sims said of the latest release of Lady Heather: > > > >> There are several cosmetic tweaks. > > > > A major new feature is the ability to write RINEX files for receivers > that can output satellite RAW observation data. RINEX files can be > processed to produce very accurate positions (typically 150-250mm for L1 > only receivers, 10mm for L1/L2 receivers). The recommended online > processor is CSRS-PPP from Natural Resources of Canada (NARCAN)... they > seem to be the only service that supports L1 only data. > > ************ > > > > In layman's terms, what does this mean with regard to being > > able to set an *AFFORDABLE* GPS RX out in the field and use it > > to do site surveys and process the recorded RINEX data later to > > establish the geo-position of each of the sites within a precision > > of +/- a few centimeters? I presume this may not be a simple as > > setting up my Trimble Thunderbolt and Lady Heather V6.0 in the > > field and gathering RINEX files for a few minutes....?? > > Even with L1/L2 survey gear, “a few centimeters” is a bit more than a > few minutes of data. So far, 24 hour records with L1 gear have given > meter level precision. > > Bob > > > > > > Mike Baker > > Micanopy, FL > > ************* > > > > > > _______________________________________________ > > time-nuts mailing list -- time-nuts@lists.febo.com > > To unsubscribe, go to > http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com > > and follow the instructions there. > > > _______________________________________________ > time-nuts mailing list -- time-nuts@lists.febo.com > To unsubscribe, go to > http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com > and follow the instructions there. >