Three different databases for gsm celltower locations

Onen at
Wed Apr 8 18:38:59 CEST 2009

Joerg Reisenweber wrote:
> Am Sa  4. April 2009 schrieb Stefan Schmidt:
>> OpenBmap likes to have more fields
>> for quality informations about GPS and GSM. 
> I strongly suggest to include fields for TimeAdvance values for each BTS.
> TA is a much better and more reliable value for distance to Base Transmitter 
> Sation than dB signal strength.
> See:
> and

I see no problem with storing the TA, to allow testing of algorithm 
using this (and thanks for bringing that to my knowledge).

Some precisions about openBmap approach. We do not try to locate or use 
location of the BTS by itself. We try to build a coverage map of every 
cell. What is the area where we have been connected to the cell. Then we 
try to find a position for this area which makes sense (e.g. barycentre).

We do not so far use the signal strength for this. We thought about 
using it nevertheless for positioning afterwards: get "position" of the 
serving cell, plus neighbours which have signal strength strong enough 
to make sense, and try to correlate all of this to refine the final 


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