Re: [gpsd-users] shared memory and fix.track

[Gary E. Miller]

Yo Roger!

On Mon, 30 Nov 2015 11:51:27 +0000
Roger Oberholtzer <address@hidden> wrote:

> I am reading data from the gpsd shared memory segment. I see quite
> often that fix.track is NaN. The other values like fix.time,
> fix.latitude, fix.longitude and fix.speed seem to update
> consistently. But fix.track is the odd man out. Anyone know why that
> might be the case?

Have you verified that your GPS is outputting fix.track but gpsd is not
passing it on?  Many GPS output fix.track at a lower rate than the
PVT data.

If that is the case then gpsd will massk (NaN) the outdated fix.track
when a newer PVT comes in.

YOu should check the setting in your PGS for fix.track output rate.

> When I do get a fix.track, it seems to be
> consistent with what I am parsing out of the raw NMEA data. My goal
> is to remove such parsing from my application, if it is possible.

My guess is that gpsd is giving any track.fix it gets, you just need to
cache that value until you expire it or get a newer value.

RGDS
GARY
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Gary E. Miller Rellim 109 NW Wilmington Ave., Suite E, Bend, OR 97703
        address@hidden  Tel:+1 541 382 8588

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