[ntp:questions] Garmin GPS 18LVC Setup but questions on best way

Maarten Wiltink maarten at kittensandcats.net
Sat Dec 27 12:26:40 UTC 2008


"George R. Kasica" <georgek at netwrx1.com> wrote in message
news:refbl4deg778k7rtgdnqcbjhajpuf3250v at 4ax.com...
[...]
>>> 3) I'd like to share the GPS/PPS signals via gpsd with another Linux
>>> system if possible would that be usable or accurate enough or should
>>> I just synch off this one at stratum 2?

>> The gps/pps signals are hardware signals. What do you mean "share
>> them?" If you mean installing a splitter so that the same PPS signal
>> is delivered to the two machines, yes you can do that. If you mean
>> something else you need to say what.

> I was hoping that gpsd would be able to simulate or transmit the pps
> similar to how it does with NEMA data but as you day they are hardware
> signals so apparently it cannot do that. Again, I don't really want to
> make the hardware any more convoluted than necessary here.

The PPS signal is a simple wire driven by one end and only read in the
most rudimentary way by the other. You can easily wire it to another
detector. Configure the other NTP to accept a PPS signal just like the
first and it'll work.

As for the NMEA data, I'd be inclined to distribute it in standard
NTP format - just configure the stratum 1 server as a server in that
other NTP server. It needs to be certain about its second boundaries
to use its PPS source, but that doesn't need to come (directly) from
a hardware reference clock.

Groetjes,
Maarten Wiltink





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