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Global => Free chat => Topic started by: franc on July 05, 2012, 21:06:14

Title: Getting location by mobile (not GPS)
Post by: franc on July 05, 2012, 21:06:14
when I get the position of my phone SGS2 by mobile carrier and not by GPS module I get it by mobile sending tower position I guess.
but when I go to the exact point on the map, there is no tower.
anyway, in Germany the providers don't tell the exact position.
so what position is this Google indicates?
Frank
Title: Re: Getting location by mobile (not GPS)
Post by: tommi on July 06, 2012, 08:00:17
I made the same experience regarding mobile network towers.

Google collects location information based on GPS (dependent on your or other phones settings) while phones are logged in a WiFi network. The information that a certain WiFi network is located at a certain position is also used later when a phone is logged into this WiFi network.
Title: Re: Getting location by mobile (not GPS)
Post by: franc on July 06, 2012, 08:38:17
I found this map for Germany:
http://emf2.bundesnetzagentur.de/karte.html (http://emf2.bundesnetzagentur.de/karte.html)
showing all tower locations (only on high zoom levels).
not with the information which providers are on each tower, but it  might be possible to ask this for each tower from BNA, I read.

my guess was that Google collects informations about cell IDs of the towers (which are available in the phones) when there are GPS signals at the same time and calculates a big map for the cell IDs. if enough phones send cell ID and GPS with different locations around the towers to Google it must be possible to make a more or less exact average position of each tower location (using also streets and paths location information, where people are likely to pass by with their android phones).

but then I think the position of the towers should be more accurate, so I think Google doesn't do it this way.

at least for Germany Google could do it better using the information of the BNA (Bundesnetzagentur).
Title: AW: Getting location by mobile (not GPS)
Post by: druki on July 07, 2012, 12:06:39
I would think it's the other way round: "Google knows" the exact location of the mobile antennas (and their cell ID) and calculates your location with a triangulation by the signals of the surrounding antennas. Your phone has to transmit the reveived information about signals via mobile network and gets the calculated position or information to calculate it in your current area (by providing the exact locations and IDs).
Title: AW: Getting location by mobile (not GPS)
Post by: druki on July 07, 2012, 12:14:53
I found a good explaining page in german language about it: http://www.elektronik-kompendium.de/sit ... 201061.htm (http://www.elektronik-kompendium.de/sites/kom/1201061.htm)
A bit more general in german Wiki: http://de.wikipedia.org/wiki/Ortsbestimmung (http://de.wikipedia.org/wiki/Ortsbestimmung)
Title: Re: AW: Getting location by mobile (not GPS)
Post by: franc on July 08, 2012, 22:18:04
Quote from: "druki"http://www.elektronik-kompendium.de/sites/kom/1201061.htm
Thank you for this link, very interesting!
Title: Re: Getting location by mobile (not GPS)
Post by: franc on July 10, 2012, 08:40:13
Ich habe nun mal bei der Bundesnetzagentur gefragt, ob es Listen von allen Sendemasten mit den jeweiligen Providern gibt, aber das gibt es nicht.
Man kann zwar über das Kontaktformular für jeden Mast, den man ja auf der BNA Karte sehen kann, erfragen, wer da drauf sitzt, das funktioniert überraschend gut, aber nicht komplett für ganz DE.
Das würde in den Bereich "Wettbewerb" fallen, der seit 1989 für die Anbieter von Mobilfunk im Fernmeldewesen zugelassen sei.
Was auch immer damit gemeint ist. Ich verstehe das so, dass die BNA nicht deren Wettbewerb stören darf.

English: There are no lists for whole Germany.