Re: Attempting to access the GD-8200 GPS

[Greg Troxel]

Stuart Blake Tener <stuart.tener@bh90210.net> writes:

> I actually ordered a VK-172 the other day and it is on its way on a
> slow boat from China.

u-blox 7, entirely reasonable.

> fine for me. I have doubts as to if this VK-172 will receive a signal
> in my house, but, I would imagine getting a U-Blox 8 based GPS board
> with an external antenna connection point ought not be too hard to
> find either as a future project. That said, for $4 and change I will
> try this device first.

Sure, it's not a bad thing to have.

> For me, logging is not of any financial transactions or that sort of
> thing, it is just system logging and assuring that the date and time
> are reasonably correct (even using the USNO NTP servers works okay for
> me, but I do like having GPS capability too, though I need to put more
> time into figuring out how to get Navit and Google Earth installed and
> working on my laptop too). Having cm or dm positional accuracy is not
> something I care about, though sure, I am fine if I could have it,
> accuracy with 1 meter is fine for plotting directions (or trying to
> accomplish RF path analysis or terrain analysis, which I rarely do,
> but is of interest to me).

You won't get 1 m, but you'll probably get somewhere 5-10 m.  After you
get the device log for a while and use gpsprof and you will likely be
surprised.  Vast numbers of people think that regular GNSS receivers,
with or without SBAS give them 1 m accuracy.  Also beware that accuracy
tends to be given in 1 sigma, but IMHO the human concept of accuracy is
95% of the time, as in "can I assume that the true position is within 1m
of the displayed postion?" more than "what is the average error".

> https://austinsnerdythings.com/2021/09/29/millisecond-accurate-chrony-ntp-with-a-usb-gps-for-12-usd/

This is more or less what I was trying to say, calibrating the delay.

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