Re: gps values delayed

[Gary E. Miller]

Yo Ralph!

On Fri, 28 Feb 2020 12:53:55 +0100
Ralph Nemitz <address@hidden> wrote:

> I' using an ublox NEO-M8P-2-11 and gpsd-3.19 go get the position.

gpsd 3.20 is out, with important updates.

Note that there are many, slightly different, versions of the NEO-M8P,
so best to send along the MON-VER parts of:
        ubxtool -p MON-VER 

> If I start gpsd, no signals occur (nmea_0.log). After a while the
> time comes (nmea_1.log). Later also latitude and longitude have the
> right values (nmea_2.log).

Yes.  That is normal.  Some GNSS receivers can take up to 30 minutes to
wake up.  Same thing happens even if you just watch the serial port with
no gpsd in the loop.

Even if the receiver starts instantly, it takes gpsd some time to
autobaud and autodetect.

> If I kill gpsd and start it new wrong values for latitude and
> longitude occur (nmea_3.log, nmea_4.log).

Notice in your log 3:

$GPRMC,105558.00,V,
                ^^^.

The V is the receiver telling you the data is invalid.  The receiver
needs more time, and/or better skyview.

> The gpsd wall called by "gpsd -n /dev/ttyACM1".

Good.

> The logfile I got by "gpspipe -r -n 50 > nmea_*.log".

Better to send the raw data, this way:
    gpspipe -R -n 50 > raw_*.log

The -r data may be from the receiver, but if the receiver is in binary
mode then that is not NMEA, it is psuedoNMEA.

> It can also happen that the values come right directly after
> switching on the board, after 30 min or 3 hours.

If it happens after 30 mins, then you likely need a better antenna.
What does you sky view look like?

> Do you have any experience with such a strange behavior?

Not strange, normal.

> Is there a 
> possibility the get more information (output with debug brought
> nothing)?

I'd like to see the skyview as reported by your reciver.

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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