Re: [gpsd-users] debugging apparent lack of multiconstellation support

[Gary E. Miller]

Yo Ben!

On Tue, 2 Jul 2019 18:19:08 -0700
Ben Crowell <address@hidden> wrote:

> I've built myself a Raspberry Pi-based handheld GPS device, and am
> having lots of fun. Thanks to those on this list who have helped to
> create and maintain this useful piece of software. My own client
> software is here
>   https://github.com/bcrowell/brownie

Cool.  How do I run it?  I get this:

# sh brownie_display.sh
/usr/lib/python-exec/python3.6/python: can't open file 
'/home/pi/Documents/programming/brownie/brownie_display.py': [Errno 2] No such 
file or directory

Looks like you hardcoded some paths?

> and my hardware is described here:
>   https://www.instructables.com/id/Handheld-GPS-With-EInk-Display/ 

Interesting.  Still using the U-blox NEO-6M GPS board?

> One of my goals for this project was multiconstellation support, but
> it seems like that is not working. The purpose of this email is to
> ask for pointers about diagnosing or fixing this.

To start, the NEO-6M only supports GPS.  What GPS are you using?

> My reason for thinking that multiconstellation is not working is that
> when I look at some sample gpsd_json data records from my receiver,
> the PRN always seems to be in the range from 1 to 64.

Not working for you.  Works fine for me on u-blox 8, u-blox 9 and
Javad GPS.

> Lack of hardware support? I have a ublox NEO-6M chip.

Oh, yeah.  Way too old.  For about $15 you can get a NEO-M8N that
supports multi-gnss.

> Out of date software? I have gpsd 3.16.

Oh, yeah.  That is over 4 years old.  Older than most of the new GNSS
sats.  You pretty much need the latest: 3.19.

> Need to turn on some feature?

Nope.  Default build should be fine.  Don't trust any distro build.

> I notice that in the gpsd_json
> documentation at https://gpsd.gitlab.io/gpsd/gpsd_json.html , there
> are a lot of fields in the "satellite" class that say "no" under
> "Always?"

Yup.  Very dependent on your GPS/GNSS device.

> Is there some way to turn these on?

u-blox does use eFuses to selectively enable features.  But the 6 is
so old you are out of luck.  Plus the eFuses are undocumented...

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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