Re: NMEA error on cat /dev/ttyACM0

[Gary E. Miller]

Yo Seán!

On Mon, 29 Aug 2022 23:02:14 +0000 (UTC)
Seán Mac Suibhne <smacsuibhne@yahoo.com> wrote:

> Hi,I have several GPS usb dongles and use them on laptops and
> raspberry pis

OK.

> This the output of lsusb for one of the dongles Bus 004
> Device 003: ID 1546:01a7 U-Blox AG [u-blox 7

The 7-series were never very good.  You should update to a newer/better
one.

> ]for some time now I
> notice the result of cat /dev/ttyACM0 gives the wrong latitude and
> longitude

How wrong?  You are too far away for my mind reading to work.  We need
to see that NMEA, and know your correct lat/lon.

> which wasnt a problem as I use them to get time and date on
> the raspberry pis

You can't know the precise time without knowing the precise location.

 When I telnet  localhost 2947 
> and put in    ?WATCH={"enable":true,"nme":true}

"nme"?  WATCH has no option "nme".

> I also get the same errors

Of course.  Garbage in, garbage out.  The u-blox sends bad data to 
gpsd and gpsd passes it on.

> However if I put in 
>     ?WATCH={"enable":true,"json":true}I get the correct lat and long

Needless to say, my long distance mind reading is still failing me.
Without seeing what you are seeing, we can't help.

> Why is cat /dev/ttyACM0 not giving the correct values for lat and
> long anymore and how can I correct it?

a) without us seeing what is wrong, we can't guess how to fix it.

b) That "cat" is direct from the u-blox.  Nothing gpsd can do about your
u-blox.

> BTW I use  
>     cat /dev/ttyACM0 | grep -a GPRMC >> gps.log  
> to record my location when I move locations on a raspberry pi

Nice to know, but useless to us without also showing us your gps.log.

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

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