Re: [Int-area] GPS over wifi

[Rob Brew <[e-mail]>]

Hi Bob,

I mean replicating the GPS data as statically defined by a server, deduced
by the incoming static IP address of the access point of the site querying
the serve
r.
The server knows the IP address being queried (which never changes), based
on the IP address for public sites which include underground rail stations.

Whilst there are GPS repeaters this approach does not require any new
hardware or cabling to be installed, making it (imho) a viable alternative
to GPS repeaters.

S. Moonesamy I will contact them now.

Thanks,
 Rob.

On Wed, Jan 22, 2020 at 8:24 PM Bob Hinden <[e-mail]> wrote:

> Rob,
>
> What exactly do you mean by GPS over wifi?
>
> Do you mean sending location/course/speed/etc. data over wifi?   Or
> somehow replicating the actual GPS satellite data?
>
> I don’t see how the latter would work giving the timing requirements.
>
> There are lots of current practice in sending NMEA sentences over IP
> networks.   I don’t know how well this is specified, but I have several
> devices that do this.
>
> Bob
>
>
>
> On Jan 22, 2020, at 4:05 AM, Rob Brew <[e-mail]> wrote:
> >
> >
> > Hi,
> >
> > Except when you can install a GPS repeater.
> >
> > We already have wireless networks covering each area of tube stations,
> this makes the porvisioing of such functionality cheaper as the
> infrastructure is already there,
> >
> >
> > I need to look at it.
> >
> > Until then, I can tell that there is a GPS GATE software that captures
> > GPS signals and puts the data (NMEA?) on IP and distributes it to IP
> > receivers.  These IP receivers might be on WiFi too.
> >
> > In this case, it might be that one needs to tell what is the format of
> > NMEA over IP.  It's very simple.
> >
> > But, agreeing that NMEA is the best thing is a different thing.  On one
> > hand, NMEA has new versions.  But it uses WGS84 which might not be the
> > best coordinate system - it is good for smartphones and users, maybe
> > cars, but in some countries it is not used to locate some important
> > points.  These use other coordinate systems.  So maybe one wants to come
> > up with a more universal coordinate system that makes everyone happy,
> > and take _that_ and put on WiFi (not NMEA).  Because, IP is such
> > universal, we should put universal things on it.
> >
> > Conversions between systems are huge opportunities for glitches to get
> > in.  These kinds of glitches ahppening very fast and added up may lead,
> > and have led, to disasters.
> >
> > > As we know the IP Address contacting the server the server contains a
> > >  map containing the GPS location of each underground site, as
> > > referenced by IP address.  The  returns the phsycial GPS location and
> > > name of the site as a JSON array.
> > >
> > > To prevent false servers reporting inaccurate information https can
> > > be used to verify the authenticity of the server.
> > >
> > > Providing this service to mobile phone user's without a current WIfi
> > >  connection i propose going one stage further, create a hidden
> > > wireless network wih the name ".location". In cases where no GPS
> > > location can be found a mobile phone's GPS system can be programmed
> > > to seek such a network providing the same service.
> >
> > Hold on, 'hidden wireless network', make sure 'hidden terminal problem'
> > is distinguished.
> >
> > A phone that cant have WiFi connection - what kind of other IP
> > connection does it have, in a place that has no GPS coverage?  Is it a
> > cellular connection in underground metro station?  If yes, it means
> > either there are cellular base stations there, or there are cellular
> > repeaters: enhance them to repeat GPS as well.
> >
> >
> > > This would require alterations to th servics as provided by mobile
> > > phone providers such as Apple and Android.
> > >
> > > If you are interested in this concept please review it (and my code),
> > >  and maybe it will become something. For a video demonstration of
> > > this service please check the link at the github site.
> >
> > I will look at the draft later.
> >
> > Alex
> >
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