Re: DBT sentences

[Gary E. Miller]

Yo Владимир!

On Mon, 14 Jun 2021 21:30:20 +0300
Владимир Калачихин <v.kalachikhin@gmail.com> wrote:

> 14.06.2021 20:27, Gary E. Miller пишет:
> > I see nothing wrong.  
> 
> Ok. I use gpsd: 3.17 (revision 3.17),

There have been changes to the DBT handling since 3.17.  You should update.

> and "gpsdecode < log.nmea"
> return depth too.
> But command "?POOL;" don't return depth.

What is command "?POOL;"?

A quick grep of gpsd source shows the only POOL that gpsd knows is the
pool.ntp.org.  It is not in "man gpsd_json" and anything not on that
man page is not part of fixed the JSON API.

> In the https://gpsd.gitlab.io/gpsd/gpsd_json.html#_poll says: "The
> POLL command requests data from the last-seen fixes on all active GPS
> devices." I treat this and the other described below as the POOL
> command will return the cached last value, not the last NMEA sentence.
> Is that not right?

You mean POLL, not POOL?  A "device" is the serial port the NMEA comes
in on.  gpsd sees the $IIDBT ass the same "device" as the GPS and all
other things incomong on that serial port.

"POLL" returns the current state on that "DEVICE".  Since your depth is
only reported intermittently, most of the time POLL will not return
the depth.

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

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