From: Don Rolph <don.rolph@gmail.com>
Date: December 13, 2021 at 7:08:03 PM EST
To: "Gary E. Miller" <gem@rellim.com>
Subject: Re: GPSD 3.22 autobauding under bullsEye
ADAFruit ultimate USB GpS:
Yes. If I have this set up with a large RF shield, this obtains a fix in seconds. However, I need a form factor similar to a Raspberry PI Zero AND I have to shield the GPS unit from the Raspberry PI RF fields. This reduces the gain of the patch antenna and thus reduces S/N ratios and increases fix time.
I am competing with a SiRF chip set, so minutes is not a major problem.
OK, I can:
- disable gpsd
- cat /dev/ttyUSB0
and I should see the native GPS stream.
Do I understand correctly?
Thanks for your help.
On Mon, Dec 13, 2021 at 6:55 PM Gary E. Miller < gem@rellim.com> wrote: Yo Don!
On Mon, 13 Dec 2021 17:06:08 -0500
Don Rolph <don.rolph@gmail.com> wrote:
> I am measuring from powering on.
Good. What model GPS? From that I can tell the number of channles
you have and make a guess as to the shape of you TTTF probabilities.
> There is no nonvolatile memory.
So every time the receiver has to guess what sats may be in view, and
start to search for them.
> As. noted, the data at this point is still preliminary, but I can
> observe using cgps that gpsd is recording achieving a fix under gpsd
> 3.22 differently than it is reporting achieving a fix under gpsd 3.17.
There have been a lot of changes in how gpsd reports data from a GPS
without a fix. So I expect you to see differences in the "No FIX" state,
but not in the "2D" or "3D FIX" state.
To compare, you can always just grabs the data from the serial port
directly and remove gpsd from the equation.
RGDS
GARY
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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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