On Sat, Oct 28, 2017 at 05:27:01PM -0700, jimlux wrote: > On 10/28/17 3:24 PM, Wayne Holder wrote: > > uBlox has a utility called u-center > > <https://www.u-blox.com/en/product/u-center-windows> that's a free > > download. You can use it to configure the various output options (and > > enable and disable different messages) and a then save this config back to > > the module as the start up default. > > > Downloaded it, hooked up the modules, found that they won't quite get a fix > indoors next to the window, but if I take it outside, it will. Oddly, the > SNR on the SVs is good enough, but there's something preventing the fix from > happening. > > Maybe it's because it's a cold start, it needed to run for a while to > acquire the almanac or something. Could be multi-path. Line of sight is blocked and the RX is receiving reflections, that traveled a bit longer. Thus, solving the navigation equations fails, or sometimes even worse, gives a wrong position. Walls, windows and water surfaces provide a multi-path signal with rather good SNR.
/Thomas, SA6CID > > > > > > > Wayne > > > > On Sat, Oct 28, 2017 at 3:12 PM, jimlux <jim...@earthlink.net> wrote: > > > > > I've got 4 NEO-7M-C modules hooked up to 7 beaglebone greens, side by > > > side, and they're not behaving the same.. > > > > > > I've got gpsd running, and I'm looking at the output of cgps and/or > > > gpsmon, as well as ppstest > > > > > > > > > Some emit NMEA sentences, others binary (ublox?) strings? > > > > > > Some get a fix and start toggling the 1pps line, others don't. > > > > > > Is there some command string one can send to them to put them into a known > > > state (cold reset?) - the one that's working the best (I.e. has a fix AND > > > toggles 1pps) seems to be putting out binary strings (when viewed with > > > gpsmon). > > > > > > > > > _______________________________________________ > > > time-nuts mailing list -- time-nuts@febo.com > > > To unsubscribe, go to https://www.febo.com/cgi-bin/m > > > ailman/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. >
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