[ntp:questions] May ntp be off by a second in case of GPS source?

Komka Péter KomkaP at prolan.hu
Wed Dec 28 19:07:48 UTC 2005

(If anyone cares:)
I guess that NTP's time, calculated from NMEA stamps, may be off by 1 or 2 

As I know, 1 or 2 seconds have to be added to the stamp's time to obtain 
current time. Because it took some (not negligable) time to
- compute the time (in the GPS receiver) (known as "position fix calculation")
- tranfer the stamp to me.
(Millisecond part may be separately set via PPS.)

I had done so calculation in my own software, and checked it against 
independend time source. (Matched.)

In the ntp source, so far I have not found such second-ajdustment.
This is why I wonder if it could give the precious time.
(I have not tested its time yet.) (No ntp-compiling experience (PC, Win).)

Komka Péter

More information about the questions mailing list