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Re: [gpsd-dev] [Thumbgps-devel] PPS over USB

From: tz
Subject: Re: [gpsd-dev] [Thumbgps-devel] PPS over USB
Date: Wed, 2 May 2012 17:43:02 -0400

Depending on the gps, there can be a dead-reckoning mode that will extrapolate things for some time (often settable).  The pps may or may not follow.

On May 2, 2012 5:19 PM, "Hal Murray" <address@hidden> wrote:

address@hidden said:
> Looking for that check in the gpsd code, I do not see it in the PPS path or
> in the NMEA path.  I wonder when that disappeared?  That may explain some
> things...  I'll go add that back in now.

I think there is another piece of fine print in that area.  I'm not sure
where I saw it, probably one of the Garmin docs.

The idea is that you can't trust the first few seconds of data when it
switches from not-enough satellites to enough.  I've seen it give bogus
position (way off) marked as valid.  I think they all happened right after
recovering from not-enough-satellites.

I'll scan log files if anybody wants examples.

These are my opinions, not necessarily my employer's.  I hate spam.

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