On 6/4/20 9:15 PM, a...@avtodoria.ru wrote: > Hello!! > > I have time jumps made by ntpd because gpsd sometimes puts wrong data to SHM > because of wrong data from gps receiver(very bad chips) > > I have only one time source in ntp.conf — 127.127.28.1 with PPS enabled > > I want to add another two internet sources for stability but at first i want > to emulate wrong data from gpsd to see how ntpd will make this time jump. > > As first step i read data from SHM when gpsd worked correctly at 14 p.m. > today UTC+3 for 30 minutes > > And after that i stopped gpsd and launched my own binary at 17:30 p.m. UTC+3 > writing that old data to SHM. I expected the great offset and the time jump > after some time(as it was when receiver lied) but what i saw was: > - without binary launched ntpd had no updates — it’s correct (no data — no > action) > - with binary launched ntpd had a little offset for all 30 minutes without > any attempt to correct system time > > please give me some help!! Maybe i don’t understand ntpd — gpsd communication > correctly or smth else > > Thank you in advance >
There's another way to communicate between gpsd and ntpd, using driver 46 (gpsd-json). It probably won't help with a really bad receiver, but it is a bit more sophisticated than the SHM memory slot, even if I say so myself. Stale data is much less of a problem with this driver. It might give different/better results, but I won't make promises here. Cheers, Pearly _______________________________________________ questions mailing list questions@lists.ntp.org http://lists.ntp.org/listinfo/questions