The Ublox M8N can send out raw measurements with messages TRK-MEAS and TRK-SFRBX for observation and navigation data: you can postprocess them to improve the accuracy. <http://www.rtklib.com/rtklib_support.htm>
On Mon, Dec 15, 2014 at 12:43 PM, Tim Shoppa <tsho...@gmail.com> wrote: > I would recommend determining your terrain's elevation using a topo map and > estimating or measuring antennas height above ground. And then excluding > survey results with wacko altitudes before averaging. > > While we often set the elevation angle mask high for timing purposes, for > survey purposes especially altitude it will likely be best to do survey > with no or very low (10 degree default?) elevation mask. The Z3801A manual > tells how to set elevation mask for at least some of your units. > > Tim N3QE > > On Mon, Dec 15, 2014 at 4:03 AM, Ole Petter Ronningen <olep...@gmail.com> > wrote: >> >> Hello, all >> >> I have a couple of GPSDOs (KS, z3805a) hooked up to a fixed outdoor antenna >> through an HP 58516 splitter. I notice that when I powercycle the GPSDOs >> (which I generally try to avoid), the position they come up with differs >> from time to time in at least the last three digits (and height in >> particular varies with up to 30m). >> >> I would like to get a better idea of what my actualt antenna location is, >> so that I can manually set the position in the GPSDOs. For that purpose I >> set up a Ublox M8N with logging in U-center, and I've collected about 250K >> readings over several days. For each reading I also log number of SV's >> used, as well as HDOP, VDOP. PDOP, thinking I would filter the list and end >> up with a subset of really good fixes.The idea is then to average the "best >> readings" and use that as my position. >> >> My question is twofold; 1) is this for some reason a bad idea? And 2) How >> do I average the numbers? I can not put my finger on it but it "feels >> wrong" to average lat, long and height independently. >> >> Any hints are greatly appreciated. >> >> Thank you! >> Ole P >> _______________________________________________ >> 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.