Re: Assisted GPS UBlox7

[Gary E. Miller]

Yo Mike!

On Mon, 13 Nov 2023 18:58:49 +0000
Mike via <gpsd-users@nongnu.org> wrote:

> I've been playing around using a U Blox 7 GPS receiever with GPSd.  I
> only have a rudimentary knowledge of GPS, so please correct any
> misunderstandings that I may have.

The 7-series was never a good choice.  You can get much newer and better
receivers for not much money.

> My understanding is that GPS not only uses the GPS signal for
> caluculating position but also has to download a stack of data too.

Yes, the Almanac and the Ephemeris, plus some secret WAAS tata.
The receiver can download them from the satellites, or be given
them over the serial port.

> This slows down time to first fix and that if a data connection
> exists, one can download this data from other sources and pass it to
> the GPS receiever.

For older receivers, yes, newerecievers, no.

  I understand this is generally refered to as
> Assisted GPS, although this is a fairly vague term that is used to
> apply to many different methods to assist GPS.

Sadly, there are no standards for such things, or public sites serving
that data.

> Reading through the UBlox manual, it does seem that the receiever
> allows the host to pass GPS data to the receiver without having to
> download it from the GPS system.

Yes, but no point for newer receivers.

> I was wondering if this was already coded into the GPSd UBlox driver?
>  I had a look at the docs and can't see anything.

It can be done with some 3rd party proprietary software, and a paid
subscription.

> I did note in the FAQ, a question about AGPS that alluded to the use
> of AGPS by GSM phones, although I assume this is not the same thing?

It is the same thing.

> Basically, what I'm asking is, can GPSd sent the ephemeris, almanac,
> etc to the UBlox GPS receiver and if not, is there another good way
> to do this?

It can, but no good way to do it, and no need with modern GPS.

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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