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Re: [gpsd-dev] [PATCH] HOWTO: calculate the average GPS offset

From: Gary E. Miller
Subject: Re: [gpsd-dev] [PATCH] HOWTO: calculate the average GPS offset
Date: Mon, 21 Oct 2013 16:52:00 -0700

Yo Andy!

On Mon, 21 Oct 2013 19:43:10 -0400
Andy Walls <address@hidden> wrote:

> Days seems like too long.

I deploy a lot of servers.  Some have good clocks, some not.  Last year
I saw two servers ntpd could not converge on at all, after weeks.   That
is when I converted to chronyd.  YMMV.

And if you server goes though busy periods that will also delay getting 
a god sync.

> The serial stream jitters *alot*.

hehehe, yeah.
> Looking at the peerstats for the GPSD/Shared Memory clock, and
> throwing out the initial 6000 seconds, I observed the following about
> the offset:
> Mean: -0.455
> Min:    -0.495
> Max:   -0.413

Is that PPS over USB or PPS over RS-232?  That is within what I see
for PPS over USB, but I have seen better.  If that is PPS over RS-232 then
something is wrong.

Gary E. Miller Rellim 109 NW Wilmington Ave., Suite E, Bend, OR 97701
        address@hidden  Tel:+1(541)382-8588

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