New config feature - time1 can declare GPS wraparound compensation

[Sanjeev Gupta]

Eric,

I am using the SHM driver , which talks to gpsd.   The presence of the "g"
suffix causes the line to be ignored.

root at ntpmon:~/ntpsec# grep refclock /etc/ntp.conf
refclock shm unit 0 refid GPS time1 0.650g flag4 1
root at ntpmon:~/ntpsec# kill -9 `pidof ntpd` ; ntpd -D 100
root at ntpmon:~/ntpsec# ntpq -pn
server=localhost No association IDs returned

ntpd.log:

2000-01-01T02:23:58 ntpd[20105]: INIT: Using SO_TIMESTAMPNS
2000-01-01T02:23:58 ntpd[20105]: IO: Listen and drop on 0 v6wildcard
[::]:123
2000-01-01T02:23:58 ntpd[20105]: IO: Listen and drop on 1 v4wildcard
0.0.0.0:123
2000-01-01T02:23:58 ntpd[20105]: IO: Listen normally on 2 lo 127.0.0.1:123
2000-01-01T02:23:58 ntpd[20105]: IO: Listen normally on 3 eth1
203.123.48.219:123
2000-01-01T02:23:58 ntpd[20105]: IO: Listen normally on 4 lo [::1]:123
2000-01-01T02:23:58 ntpd[20105]: IO: Listen normally on 5 eth1
[2405:fc00:0:1::123]:123
2000-01-01T02:23:58 ntpd[20105]: IO: Listen normally on 6 eth1
[fe80::204:23ff:feb8:1c1e%3]:123
2000-01-01T02:23:58 ntpd[20105]: IO: Listening on routing socket on fd #23
for interface updates
2000-01-01T02:23:58 ntpd[20105]: INIT: This system has a 32-bit time_t.
2000-01-01T02:23:58 ntpd[20105]: INIT: This ntpd will fail on
2038-01-19T03:14:07Z.
2000-01-01T02:23:58 ntpd[20105]: PROTO: 0.0.0.0 c01d 0d kern kernel time
sync enabled
2000-01-01T02:23:58 ntpd[20105]: PROTO: 0.0.0.0 c012 02 freq_set kernel
39.594910 PPM
2000-01-01T02:23:58 ntpd[20105]: PROTO: 0.0.0.0 c016 06 restart
2000-01-01T02:23:58 ntpd[20105]: NTSc: Using system default root
certificates.


-- 
Sanjeev Gupta
+65 98551208     http://www.linkedin.com/in/ghane


On Sat, Aug 17, 2019 at 1:41 AM Eric S. Raymond via devel <devel at ntpsec.org>
wrote:

> I've just pushed a change that interprets a 'g' suffix on a clock time1
> fudge option as an instruction to add the number of seconds in a
> 1024-week GPS era. There can be more than one g. Using this, you can
> compensate for era rollover in old GPS devices.
>
> Credit to James Browning for the idea. It's actually done at the
> scanner level, so it will work for other double-valued options such
> as the time2 fudge - not that I expect that to be used.
>
> If you have a GPS old enough to require wraparound compensation,
> please test; I don't think I do anymore.
>
> I've also updated the driver documentation, pointing out where this
> option is likely to be of use, and the NEWS file.
>
> Mark: once we've tested this it might merit a point release.
> --
>                 <a href="http://www.catb.org/~esr/">Eric S. Raymond</a>
>
> You know why there's a Second Amendment?  In case the government fails to
> follow the first one.
>          -- Rush Limbaugh, in a moment of unaccustomed profundity 17 Aug
> 1993
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