Re: -GPSD 3.22 autobauding under bullsEye

[Gary E. Miller]

Yo Don!

On Tue, 14 Dec 2021 08:25:56 -0500
Don Rolph <don.rolph@gmail.com> wrote:

> Nice module, but I really need a USB connection for the present
> design. However, there seem to be a number of GPS modules on eBay at
> your link, Since the GPS unit's only requirements are that it be
> within the Pi Zero form factor AND connect with USB, substitutes are
> straightforward and I will poke some more.  Thanks!

I thought the Adafruit was serial?  No matter, their are a lot
of USB ones too.

> What is the negative downside of the Adafruit GPS modules based on
> the MT3333 chipset compared to say the U-blox chip sets?

You need to specify which generation u-blox.  The MT3333 was almost
as good as the u-blox 7.  Way back when.   But the, now commodity, u-blox
8 blows it away.  For high performance the u-blox 9, and just introduced
10, are far suppior.

1) much more sensitivity
2) many more receive channels, and thus much fast TTFF
3) better interference and jamming protextion.
4) some models will use a lot less power.
5) the ubx binary messages are much richer, and better specified, than NMEA
6) very configurable to any use case.

> It is possible the foil is acting as a ground plane increasing
> sensitivity.  However that does not then explain why it is highly
> sensitive in the open away from the assembly, and apparently desensed
> near the assembly.

I have an Adafruit HAT, and do not see this effect, The difference being
that I use an external antenna.  So that leads me to beleive you have an
antenna effect.

But, get rid of the MT333x, and you will not have those problems.  I prefer
to debug good stuff, not shit.

> And  any further leads/comments on alternate chip sets for GPS modules
> within the PI Zero form factor AND using USB would be much
> appreciated!

Pretty much anything u-blox 8.  u-blox 9 is better, if your budget 
allows.  u-blox parts with native USB (M8030) will be best for you.

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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