[time-nuts] Warped back to 1993

[Martin Burnicki]

Bob Camp wrote:
> Hi
>
> … and since NTP is open source, doing the hack is not dependent on getting a new firmware image for the GPS.

Hacking ntpd is one possibility, with the risk that a workaround for 
some broken GPS receiver also affects GPS receivers which are working 
correctly.

At least in some of ntpd's refclock drivers you can configure a fixed 
offset using a "fudge time1 ..." command., e.g. for the parse driver

fudge 127.127.8.0 time1 7200

would add a 7200 s offset to the time from the refclock. As far as I 
know this also works for larger offsets, at least with the parse driver, 
and this possibly can also be used to fix a constant offset for broken 
GPS receivers, depending of the refclock driver used.

Anyway, I think it's worth a try, and it would not require any code 
change in ntpd or the firmware.

Martin