[ntp:questions] Suggested gps devices for use as a time source for ntpd

Hal Murray hal-usenet at ip-64-139-1-69.sjc.megapath.net
Tue Aug 7 08:11:11 UTC 2007


>Now most of the nav units have usb connectors so I assume that's so they
>can be used for this purpose. I gather I also have to look for ones that
>support NMEA or PPS output is this still correct?

USB and timekeeping is not a good combination.

If you want good timekeeping, you want a unit with PPS.  That
should get you within 10s of microseconds.  Without a PPS signal,
I'd expect 10s of milliseconds.


>Any suggestions for gps nav units that support ntp on linux?

The best low-cost GPS unit that I know about is the
Garmin GPS 18 LVC.  NB: You neeed the -LVC.  The other
versions of the GPS 18 don't have PPS.

It needs a serial port and 5V power.  You can get the power
from a USB connection.  It's under $100.  "Some assembly
required."  (No big deal if you know how to use a soldering iron.)

-- 
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