Re: [ntp:questions] Re: Garmin GPS18USB and NTP on Win2k

On 2005-06-26, Brad Knowles <brad@xxxxxxxxxxxxxxxxxxx> wrote:

> At 6:32 PM -0400 2005-06-25, Richard B. Gilbert wrote:
>
>> USB does work well for navigation but I would not use it for timing.
>
> And I'm not sure that this particular model of GPS device is good
> for timing use even if the USB interface didn't add its own set of
> problems.

The GPS-18LVC provides a PPS output with a claimed accuracy of 1us.

Mine usually produces results like this (summarized w/ peer.awk):

ident cnt mean rms max delay dist disp
===============================================================
127.127.20.0 5235 -0.000 0.003 0.014 0.000 0.270 0.248
127.127.7.0 172 -0.467 0.418 2.435 0.000 26.100 3.086

(127.127.20.0 == GPS_NMEA, 127.127.7.0 == CHU_AUDIO)

Not bad for an $80 (including delivery) GPS that only sees about half of
the sky.

--
Steve Kostecke <kostecke@xxxxxxxxxxx>
NTP Public Services Project - http://ntp.isc.org/
.

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