GPS as a source of time like NTP

Russell Sears sears at
Sun Jul 27 08:29:29 CEST 2008

Daniel Willmann wrote:
> Just had a look at the gpsd sources. There's a gpsd/refclock_nmea.c in
> there. I guess it should be pretty easy (at least doable :-) to make a
> refclock_dbus/gypsy.c and listen to the specific dbus signals.

Getting this to work would be great!  My FR drifts by a few minutes 
every day.   I think ntp has code to adjust for this so the clock won't 
jump around every time it talks to a high-quality time source.

Also, I've heard that GPS satellites don't take leap seconds into 
account.  That could cause trouble for people using ntp and gps data to 
set clocks, since the times will disagree by a few seconds.  It might be 
good to map from "GPS time" to "real time".


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