[OSM-talk] Good deal on Garmin GPS unit

[Nick Black]

Ok, this was what I interpreted as meaning that the Sirf  Star II receives
signals from GSM networks:

 "With its rapid time-to-first-fix and high sensitivity, the SiRFstarIII
architecture is designed to meet the rigorous demands of wireless and
handheld LBS applications, and provides superior location performance, both
indoors and out, for 2G, 2.5G, 3G asynchronous networks."


Thats taken from http://www.sirf.com/products-ss3.html

Nick




On 7/5/06, Nick Black <nickblack1 at gmail.com> wrote:
>
>
>
> On 7/5/06, J.D. Schmidt <jdsmobile at gmail.com> wrote:
> >
> > Nick Black wrote:
> > > On 7/5/06, Andy Armstrong <andy at hexten.net> wrote:
> > >>
> > >> On 5 Jul 2006, at 10:24, Dan Karran wrote:
> > >> > - it's rather large compared to my eTrex (though it's relatively
> > >> > light)
> > >>
> > >> Huge, innit? :)
> > >>
> > >> > - it didn't manage to get a lock on 3 satellites whilst walking to
> > >> > work, whereas I think my eTrex does... I should really have waited
> > to
> > >> > let it get a lock before walking, but I was late already  :)
> > >>
> > >> Mine took nearly half an hour to get its head together - I thought it
> > >> was faulty. Eventually it worked where everything was and now it gets
> >
> > >> a fix within < 1 min from power up and gets a +/- 4m 3d fix shortly
> > >> thereafter.
> > >
> > >
> > > GPS units can't actually locate themselves anywhere on the
> > Earth.  They
> > > need
> > > to know at least which quater-sphere they are in to be able to carry
> > out
> > > the
> > > regression necessery to determine their position.  That's why the
> > first
> > > time
> > > you use a unit (or if you turn it off, travel a significant distance
> > and
> > > turn it on again) it takes a while to sort itself out.  My Garmin GPS
> > 60
> > > took a good 15 mins to determine my position the first time I turned
> > it on,
> > > and I even told it I was in London.
> >
> > If your GPS takes 15 minutes for a first fix, something is wrong with
> > it, especially if it is a newer GPS. What you might be thinking of, is
> > the fact that it will take about 15 minutes to get a complete ephemeris
> > and almanac down. But the GPS should be able to provide a first fix and
> > be able to provide navigational data long time before that.
>
>
> First fix from a totally cold start?  The last time it was turned on was
> in Taiwan, then in London.  Do you have a Garmin unit?
>
>
> > Units with teh Sirf Star III chip
> > > shouldn't have this problem as they using GSM cells to locate
> > themselves as
> > > well as GPS satellites.
> >
> > Oh ? Thats a new one. The SiRF III chipsets are NOT GSM enabled, and do
> > not contain any logic that allows it to pick up GSM cell transmissions.
> > Some multifunction devices that use SiRF III chipsets for the GPS
> > functions contain additional logic in order to communicate via GSM for
> > updated trafficdata/use as a cellphone, and they might be using the GSM
> > cells for additional locationpositioning.
> > But saying that "Units with the Sirf Star III chip" are using GSM cells
> > is not correct.
>
>
> Thats what I thought until I someone pointed out this article to me:
>
> http://www.sirf.com/Downloads/Collateral/GSC3(f)_6.20.05.pdf<http://www.sirf.com/Downloads/Collateral/GSC3%28f%29_6.20.05.pdf>
>
> and another that I can't find at the moment, think it was on Sirf's
> website.
>
> Its about all the documentation I could find about Sirf Star III, the
> mention of GSM is a *bit* flakey - the chip must at least be compatible with
> GSM receivers then?
>
>
> Nick
>
> J.D. "Dutch" Schmidt
> >
>
>
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