Subject: [Int-area] GPS over wifi for underground locations -- submitted draft RFC.

From: Rob Brew <[email-masked]>
Date: Mon, 20 Jan 2020 17:21:35 +0000

Dear all.

I have submittetd the following draft RFC for approval.

Obviously whilst underground mobile phone users at public locations, such
as the London underground, will not be able to know their GPS location, as
the GPS signals cannot penetrate the earth.  I have submitted a RFC draft
at https://tools.ietf.org/html/draft-brew-intarea-underground-01 to bypass
this problem, as well as a server application in Java at
https://github.com/rydal/underground .

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.

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.

Thanks,

      Rob Brew.

---

From: Erik Kline <[email-masked]>
Date: Mon, 20 Jan 2020 13:01:21 -0800

Rob,

As you may well know there was once a working group (geopriv
<https://datatracker.ietf.org/wg/geopriv/about/>) where many similar topics
were discussed.  That's concluded now, but I wonder if your document would
be more appropriate for consideration in artarea or even gendispatch.

On Mon, Jan 20, 2020 at 9:22 AM Rob Brew <[email-masked]> wrote:

> at https://tools.ietf.org/html/draft-brew-intarea-underground-01 to
> bypass this problem, as well as a server application in Java at
> To prevent false servers reporting inaccurate information https can be
> used to verify the authenticity of the server.
>
> _______________________________________________
> Int-area mailing list
> [email-masked]
> https://www.ietf.org/mailman/listinfo/int-area
>

---

From: Brian Haberman <[email-masked]>
Date: Mon, 20 Jan 2020 16:12:14 -0500

There was both the geopriv WG and the geojson WG. I would second Erik's
recommendation to contact the ART area on this type of work.

Regards,
Brian

---

From: Rob Brew <[email-masked]>
Date: Tue, 21 Jan 2020 03:12:46 +0000

Thank you both.

Looking at the artarea ietf page i can't find their mailing list.
Please can someone let me know it, or should i message the chair?

Rob.

---

From: Erik Kline <[email-masked]>
Date: Mon, 20 Jan 2020 22:54:50 -0800

Ah yeah, that's a little strange.

Perhaps better is ART dispatch, then:

    https://datatracker.ietf.org/wg/dispatch/about/

Sorry for the confusion.

---

From: Stewart Bryant <[email-masked]>
Date: Tue, 21 Jan 2020 07:15:53 +0000

Given that when I turn off Wifi, my phone asks me to turn it back on to improve location accuracy there must me something similar already deployed.

I think that the current system is based on using the SSIDs which have the advantage that they are a broadcast signal and do not require that you have permission to log on to the WiFi.

In the underground case, providing the map on the phone with the stations SSID would be a passive alternative which I suspect is already deployed, and is more in the spirit of the GPS approach.

- Stewart

Sent from my iPad

> On 20 Jan 2020, at 17:22, Rob Brew <[email-masked]> wrote:
> 
> 
> Dear all.
> 
> Obviously whilst underground mobile phone users at public locations, such as the London underground, will not be able to know their GPS location, as the GPS signals cannot penetrate the earth.  I have submitted a RFC draft at https://tools.ietf.org/html/draft-brew-intarea-underground-01 to bypass this problem, as well as a server application in Java at https://github.com/rydal/underground .
> 
> 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.
> 
> 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.
> 
> Thanks,
> 
>       Rob Brew.
>

---

From: Alexandre Petrescu <[email-masked]>
Date: Tue, 21 Jan 2020 13:32:25 +0100

Le 21/01/2020 à 08:15, Stewart Bryant a écrit :
> Given that when I turn off Wifi, my phone asks me to turn it back on to 
> improve location accuracy there must me something similar already deployed.

That is a problem of the GUI.  The GUI gives a wrong sense.

The WiFi improves accuracy of location to the extent it helps the phone 
to access the google database which contains a list of locations of 
Access Points (by MAC) address.  Locally measuring the power it is 
possible to determine a rather fuzzy location based on WiFi AP 
positions, but which is more than nothing (nothing is present when GPS 
is absent).

In a sense yes, 'improve location accuracy' when GPS is absent or very 
bad (e.g. DOP higher 3 or 5), can be obtained with WiFi.

Similar to WiFi there is also location based on GSM positioning.  It's 
still very fuzzy, but better when there is no GPS coverage.

Absence of GPS coverage also has multiple meanings.  In some places GPS 
satellite dont reach because of the place being wrong (e.g. underground 
and without GPS repeaters); but other times GPS is absent because of 
human desire (check exercise military Florida recent nanog post). 
Moreover, GPS coverage might be less preferred to be used because of 
other Layer-8 reasons, where one might prefer Galileo, Glonass, Beidou, 
others.  These reasons are even further fuzzied by a possibility where 
in _some_ of these places, GPS might be preferred in complimentarity, 
whereas in others no.  For example, use Galileo complimented with GPS 
might give more reliable results, yet nobody talks about complimenting 
Galileo with Glonass, for example, or complimenting them all into one, 
despite being often all available in one place.

GUI expression is hard to tell in just one small screen with all these 
factors.

> I think that the current system is based on using the SSIDs which have 
> the advantage that they are a broadcast signal and do not require that 
> you have permission to log on to the WiFi.

YEs.

> 
> In the underground case, providing the map on the phone with the 
> stations SSID would be a passive alternative which I suspect is already 
> deployed, and is more in the spirit of the GPS approach.

In this, you mean 'GPS' as the device my car carries.  The car also has 
odometer (dented wheel that counts turns of bigger wheel).  Smartphones 
dont have odometers.  Cars with GPSs and good maps, like submarines, can 
maintain very accurate positioning when GPS satellite are invisible for 
longer time and distance.  Cars and submarines also use additional 
sensing of their environment, like in 'ranging', which helps them build 
maps, and then orient, build again, until a near perfect localisation is 
obtained.

Smartphones might use their inertial central to act when GPS is 
invisible but the trials of in-building movements dont exhibit too high 
accuracy.  Smartphones are carried in pockets - cant see, can't 
'ranging'.  They might use the watches on wrists, but rarely can these 
see either.

Alex

>> Obviously whilst underground mobile phone users at public locations, 
>> such as the London underground, will not be able to know their GPS 
>> location, as the GPS signals cannot penetrate the earth.  I have 
>> submitted a RFC draft at 
>> https://tools.ietf.org/html/draft-brew-intarea-underground-01 to 
>> 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.
>>
>> 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 
>> This would require alterations to th servics as provided by mobile 
>> phone providers such as Apple and Android.
>>

---

From: Alexandre Petrescu <[email-masked]>
Date: Tue, 21 Jan 2020 13:47:13 +0100

Hi,
There are enourmously many things here, and thank you for posting.

There might be some systemic engineering problems.

Le 20/01/2020 à 18:21, Rob Brew a écrit :
> location, as the GPS signals cannot penetrate the earth.

Except when you can install a GPS repeater.

The problem of lack of ability to penetrate the Earth is known for 4G as
well, and for bluetooth and for wifi.

There are some GPS repeaters in some places.  (I did install myself
some).  The problem there is the following: make sure you have the right
to do it, license, regulator.  Use long but very high-quality cables (RF
- Radio Frequency), which are usually thick and expensive.  The GPS
repeater is cheap, 30Euros or so, off the shelf.  Use good GPS antennas
in the place where GPS coverage is there, protect from vandalism, tell
others what is good for, for long time.  Ideally, write software that
modifies the position to add depth with the known number of meters, to
the GPS signal.  That's not really necessary, because people might not
need to orient on 3D, maybe 2D on the same level would be sufficient.

There are some deployments in road tunnels in which Bluetooth devices 
are spread along the road underground and claim to repeat localization 
in a step-by-step manner.  It is a concept, with an IoT device on the 
market, but which suffers from systemic engineering problems as well.  I 
dont think it will fly.

> I have submitted a RFC draft at 

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.

> To prevent false servers reporting inaccurate information https can
> be used to verify the authenticity of the server.
> 
>  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.

> 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

> 
> Thanks,
> 
> Rob Brew.
> 
> 
> _______________________________________________ Int-area mailing
> list [email-masked]

---

From: Alexandre Petrescu <[email-masked]>
Date: Tue, 21 Jan 2020 13:48:40 +0100

change the topic to something else from 'submitted draft RFC', because 
oftentimes it takes an enormous amount of time between draft state and 
RFC state - several years during which there are many opportunities for 
this to disappear altogether or pursued under a completely different name

Le 20/01/2020 à 18:21, Rob Brew a écrit :
> https://tools.ietf.org/html/draft-brew-intarea-underground-01 to bypass 
> 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.
> 
> and maybe it will become something.