Re: gps_data_t->status information of gpsd 3.19

[Gary E. Miller]

Yo Appelt!

On Tue, 10 Dec 2019 09:53:09 +0000
Appelt Andreas <address@hidden> wrote:

> We were very happy to see the 'Added values for gps_data_t->status'
> in the 3.19 version of gpsd. /* GPS status -- always valid */
>     int    status;                 /* Do we have a fix? */

Glad you like it.

> Is there a reason why you did not use the nmea0183 status values?

The nice thing about standards is there are so many to choose from.

I refuse to pay NMEA for the NMEA 1083 standard, so all I have to go on
is reading what other people read about NMEA.  So I went with the
u-blox "standard" as that is the doc I had as well as a receiver
that implemented it.  It also covers many more conditions than the
limited ones in NMEA 0183.

> Meaning, why not using that status as is?

No two message types use similar status.  Gotta pick one, or do them
all separate.  But seperate not gonna happen.

> And set
> #define STATUS_RTK_FIX       4     /* yes, with RTK Fixed */
> #define STATUS_RTK_FLT       5     /* yes, with RTK Float */
> #define STATUS_DR            6     /* yes, with dead reckoning */

Because then there would be three, then four, then soon more
independent status varaiables, instead of just two status variables.
The point is that those 3 values you just mention fit nicely into the
more complete status that gpsd uses from the u-blox doc.

> (I am asking because our customers

Wow, if you have paying customers, care to share that cash?

> are used to and familiar with the
> GGA notation.)

Which is why gpsd also passes on the GGA.

> I also noticed that the new status in the driver_nmea2000.c file was
> not adapted: //  printf("mode %x %x\n", (bu[31] >> 4) & 0x0f, bu[31]);

Because NMEA 2000 doc is even harder to come by than NMEA 0183 doc, and
gpsd has no NMEA  2000 regressions.  We don't touch what can not be
confirmed against doc, regressions and/or lab hardware.

Feel free to send this project NMEA 2000 doc ($$), NMEA 2000 regressions,
NMEA 2000 test samples and/or NMEA 2000 merge requests.

Since you have customers, you can share your budget to get it done.

> Are there plans to adapted that in the future in order to support RTK
> and float RTK?

Nope.  Not without doc, regressions, a working receiver or a merge request.

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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