[guardian-dev] detecting mobile phone location

Matej Kovacic matej.kovacic at owca.info
Tue Feb 11 09:20:08 EST 2014


I have a contact with one of the human rights activists in Sudan. The
person told me a story, that some Somalian indigenous people, who are
opressed by the Sudanian regime did the test with mobile phones.

They turned the mobile phone on, put it on some corner and went several
hundert meters away. In an hour airplane came and bombed the house.

I am quite curious how is that possible if there is no mobile signal
there. Of course, I don't know the details, it is possible, that mobile
signal is there. As far as I know, it is possible to connect to a base
station from up to 30 km away, but I am not sure how triangulation works
if there is only one base station nearby.

Now they have a question: how to protect from this? They came with an
idea that they will simply remove SIM card and communicate via wi-fi.
System would create with meshing network where each mobile phone would
be a relay node.

There is an application from Swiss mountain rescue service called Uepaa
(http://www.uepaa.ch), which is doing similar thing.

There is also interestin slovenian project doing this with home wi-fi
routers: https://wlan-si.net/en/ and https://nodes.wlan-si.net/.

However, I am not sure how safe is this (removing SIM card), because
even if you remove SIM card, you are still able to make an emergency
call, which means you still see the network and network still can see
you. I think all radio part should be completely switched off / removed.

However, there is a problem how to do this...?

Any idea how to privide safe communications in such a case? Because
encryption is not a solution, problem is location privacy.



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