[ntp:questions] garmin 18x and linux

unruh unruh at wormhole.physics.ubc.ca
Mon Sep 5 15:04:54 UTC 2011


On 2011-09-05, Miroslav Lichvar <mlichvar at redhat.com> wrote:
> On Sat, Sep 03, 2011 at 08:05:21AM -0500, steven Sommars wrote:
>> I monitored Garmin LVC (corrected firmware) NMEA time and saw variance of up
>> to 50msec.  I wonder if the variation in NMEA time depends on GPS signal
>> quality.
>
> I'm wondering what is the cause of the variance too.
>
> With 18x LVC (firmware 3.70) I see errors up to 150 ms. That
> wouldn't be that bad if it was randomly distributed.
>
> A capture over 30 hours:
> http://mlichvar.fedorapeople.org/tmp/18x_nmea.png

This was captured how? Is that the beginning or the end of the nmea
sentence?
You have some where the offset is negative. Does this really mean that
the nmea came in before the beginning of the second it referred to?


>




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