[ntp:questions] PPS versus serial offset

Steve Kostecke kostecke at ntp.org
Wed Aug 28 12:26:03 UTC 2013

On 2013-08-28, detha <detha at foad.co.za> wrote:

> Done the 'let it run for 24 hours, take average offset between PPS and
> serial reading, and use that as time1 for the gpsd line in ntp.conf.'

Where did you find that bad advice?

A timing GPS provides two pieces of information:

1. The PPS signal which marks the seconds

2. NMEA sentences which label the seconds

The PPS signal is emitted at the beginning of each second and is

The NMEA sentences are emitted when the GPS receiver is not busy with
other tasks and can occur at any time during the relevant second.

Steve Kostecke <kostecke at ntp.org>
NTP Public Services Project - http://support.ntp.org/

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