Richard B. Gilbert schrieb: > David Woolley wrote: >> Richard B. Gilbert wrote: >> >>> To turn your equipment on after months of downtime and expect it to >>> lock on to the correct time with millisecond accuracy within seconds >>> is asking for a hell of a lot. >> Not really. He's starting a GPS receiver at the same time and that has >> to lock to 50ns. >> >> Doing it on a general purpose computer is more difficult, but not >> particularly impossible. > > Even with GPS and a full four satellite fix, ten seconds to synchronize > is extremely ambitious!! You can set the time to within whatever > precision the hardware and software support but that is only half the > problem. You also need to set the correct clock frequency. On a cold > start, the clock frequency is a moving target as the hardware warms up. > > I would expect to wait at least thirty minutes for the system to > stabilize with both the correct phase (time) and frequency.
To transfer the full almanac of GPS it takes roughly 12 minutes from a cold start. Then the receiver knows everything there is for it to know. Some receivers (like mine) you can tell it's location, wich gets you in the 10 s range for precise time. Then again, who claimed, it has to be 10 s? I would be very happy with these 12 mins.. _______________________________________________ questions mailing list [email protected] https://lists.ntp.org/mailman/listinfo/questions
