From: Petter Reinholdtsen Date: Fri, 29 Sep 2017 08:31:24 +0000 (+0200) Subject: Generated. X-Git-Url: http://pere.pagekite.me/gitweb/homepage.git/commitdiff_plain/bd8be5e32d0b16b655964fc3ebeabea7848f4c35 Generated. --- diff --git a/blog/Visualizing_GSM_radio_chatter_using_gr_gsm_and_Hopglass.html b/blog/Visualizing_GSM_radio_chatter_using_gr_gsm_and_Hopglass.html new file mode 100644 index 0000000000..aec6265e11 --- /dev/null +++ b/blog/Visualizing_GSM_radio_chatter_using_gr_gsm_and_Hopglass.html @@ -0,0 +1,489 @@ + + + + + Petter Reinholdtsen: Visualizing GSM radio chatter using gr-gsm and Hopglass + + + + + + +
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+ Petter Reinholdtsen + +

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Visualizing GSM radio chatter using gr-gsm and Hopglass
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29th September 2017
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Every mobile phone announce its existence over radio to the nearby +mobile cell towers. And this radio chatter is available for anyone +with a radio receiver capable of receiving them. Details about the +mobile phones with very good accuracy is of course collected by the +phone companies, but this is not the topic of this blog post. The +mobile phone radio chatter make it possible to figure out when a cell +phone is nearby, as it include the SIM card ID (IMSI). By paying +attention over time, one can see when a phone arrive and when it leave +an area. I believe it would be nice to make this information more +available to the general public, to make more people aware of how +their phones are announcing their whereabouts to anyone that care to +listen.

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I am very happy to report that we managed to get something +visualizing this information up and running for +Oslo Skaperfestival 2017 +(Oslo Makers Festival) taking place today and tomorrow at Deichmanske +library. The solution is based on the +simple +recipe for listening to GSM chatter I posted a few days ago, and +will show up at the stand of Åpen +Sone from the Computer Science department of the University of +Oslo. The presentation will show the nearby mobile phones (aka +IMSIs) as dots in a web browser graph, with lines to the dot +representing mobile base station it is talking to. It was working in +the lab yesterday, and was moved into place this morning.

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We set up a fairly powerful desktop machine using Debian +Buster/Testing with several (five, I believe) RTL2838 DVB-T receivers +connected and visualize the visible cell phone towers using an +English version of +Hopglass. A fairly powerfull machine is needed as the +grgsm_livemon_headless processes from +gr-gsm converting +the radio signal to data packages is quite CPU intensive.

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The frequencies to listen to, are identified using a slightly +patched scan-and-livemon (to set the --args values for each receiver), +and the Hopglass data is generated using the +patches +in my meshviewer-output branch. For some reason we could not get +more than four SDRs working. There is also a geographical map trying +to show the location of the base stations, but I believe their +coordinates are hardcoded to some random location in Germany, I +believe. The code should be replaced with code to look up location in +a text file, a sqlite database or one of the online databases +mentioned in +the github +issue for the topic. + +

If this sound interesting, visit the stand at the festival!

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Tags: debian, english, personvern, surveillance.
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