Re: [gpsd-users] cgps/xgps NO FIX but gpsmon works?

[Gary E. Miller]

Yo Noeneel!

On Fri, 12 Jul 2019 02:47:23 +0000
Noeneel Sharma <address@hidden> wrote:

> > You can get a nice modern GPS for $15 or $20.  So easy to fix,
> > throw away that old thing.  
> 
> Ooooh really? Any suggested models that I should look at that would
> play nice with a Raspberry Pi?

If you want good timing, then you want a GPS with PPS out.

These are $20, u-blox NEO-M8N, from China:

https://www.ebay.com/itm/GLONASS-NEO-M8N-GPS-Module-UBLOX-GPS-Navigation-Board-for-Flight-Control-sztop/183780263635

Or you can stay with USB, but the time will be very rough.  Not good
enough for NTP:

Here is a cheap USB one:

https://www.ebay.com/itm/Stratux-GPYes-2-0-u-blox-8-GPS-unit/123523753874

Just be sure to get a u-blox of version 8.

> > Easy to get: gpspipe -R -n 300 > raw.log
> > 
> > Or the SHM failure could also be the killer item.
> > 
> > When that finishes, just send the raw.log file here.  
> 
> Attached

here is the key:

$GPRMC,003345.801,V,2727.0220,S,15302.6071,E,0.00,0.00,060180,,,N*69
                 ^^^

Notice the V?  That is the GPS telling you not to use that fix.

So there are no valid fixes in your capture file.

That V is instead an A when you have valid fixes.

gpsd does not pass on invalid data.  Otherwise people
mistake it for good data.
RGDS
GARY
---------------------------------------------------------------------------
Gary E. Miller Rellim 109 NW Wilmington Ave., Suite E, Bend, OR 97703
        address@hidden  Tel:+1 541 382 8588

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    "If you can’t measure it, you can’t improve it." - Lord Kelvin

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