[ntp:questions] Slow convergence of NTP with GPS/PPS

Hal Murray hal-usenet at ip-64-139-1-69.sjc.megapath.net
Fri Oct 24 18:31:27 UTC 2008

>My own experience suggests that, at least with a hand-held GPS, it can be 
>a lot longer than 45 seconds.  That figure may only apply if the GPS has a 
>180-degree clear view of the sky.  But the GPS18 LVC does usually recover 
>quickly enough (mine has a less than 180-degree sky FoV).

The 45 second number if probably marketing.  I'm not sure
how to translate that into reality.

I wouldn't be surprised if older units took a lot longer.

>If we accept 45s, is that shorter than the typical system boot time from 
>cold?  Could the system boot be delayed enough so that the GPS was 
>guaranteed to be ready by the time it was needed?

With a bit of work, you can boot in much less that 45 seconds.

These are my opinions, not necessarily my employer's.  I hate spam.

More information about the questions mailing list