Re: [Int-area] GPS over wifi

[Bob Hinden <[e-mail]>]

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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