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Re: [gpsd-users] Controlling the gpsd update rate
From: |
Gary E. Miller |
Subject: |
Re: [gpsd-users] Controlling the gpsd update rate |
Date: |
Tue, 27 Feb 2018 17:37:04 -0800 |
Yo Deven!
On Tue, 27 Feb 2018 17:20:25 -0800
Deven Hickingbotham <address@hidden> wrote:
> > BTW, recent reports on this list that some u-blox skip some fixes
> > at 10Hz.
>
> I'm still investigating this, but the reports would be consistent
> with your evaluation of the output files I sent you.
Cool.
> I searched the u-blox forum and they recommend turning off output on
> the interfaces you are not using and pare the remaining messages
> being sent to the bare minimum. This would include reducing the
> frequency of certain messages like satellite position.
Yeah, but you dod not have much to cut.
> How does gpsd handle messages being sent a various frequencies?
When gpsd gets stuff, it passes it on. gpsd does not care about
what or how fast. You care you get a complete fix. you likely want just
UBX-NAV-PVT.
> Suppose lon/lat are sent at 10hz and satellite data every 5 seconds?
Fine. But why do you care about the sats as long as you got PVT?
> Would epx and epy (which I assume are based on satellite data) be
> zero during the intervening 5 seconds or would they be the last
> calculated value?
Nah, gpsd does not make up data, it just passes on what it gets,
when it gets it.
And don't take epx/epy/etc seriously.
> If I allow gpsd to optimize the settings, does the optimization only
> occur at startup?
Yup.
> I am trying to understand what gpsd will do if I
> later use gpsctl to change a setting.
Well, right now, that can be flakey. But the code tries to just pass
on what you sent.
> If gpsd only optimizes at
> startup, then my subsequent change would not be overridden.
Correct.
> If it is
> continually optimizing, then it might override my change.
Nope.
> Finally, if I use the -b option, does this mean gpsctl and commands
> sent to the Unix domain socket will not work?
They may not work even with -b. :-)
You are in an area that has been long neglected and I'm discovering bit
rot.
The common approach is to use u-center to set your, then run gpsd with -b.
I'd eventually like to replace u-center, not gonna happen soon.
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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