As an exercise it might be fun to try to do the best you can with just NMEA. But practically speaking even my very $10, 8-channel motorola GPS receiver can output a PPS to about 50ns. Better then needed for NTP. You friend in the Gobi desert would be better off my $10 GPS
That said, if you had a good local oscillator you could make a decent GPSDO using NMEA only with a VERY long time constant On Mon, Aug 1, 2016 at 9:23 AM, Mark Sims <hol...@hotmail.com> wrote: > Well, the whole point of the exercise is to see how well you can do if you > DON'T have an internet connection, a 1PPS signal, or a stratum 1 time server > available... only the humble messages coming from a 10 dollar GPS receiver. > Try getting a net connection in the middle of the Gobi desert (where one user > uses Lady Heather's time sync feature to keep their system clocks reasonably > accurate). > > > If you can put the receiver into a binary message mode, you can usually do > better than NMEA (but, surprisingly, usually not by much). And by selecting > a receiver that has known good / stable message timing you can do > surprisingly well. > > > ---------------------- > > >> I feel that using the serial NMEA stream would, today, be a last resort, as >> an Internet sync would be considerably better. Would you agree with that? > > > _______________________________________________ > 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. -- Chris Albertson Redondo Beach, California _______________________________________________ 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.