AGPS Thoughts

Sebastian Hammerl list-openmoko at
Tue Mar 31 00:03:18 CEST 2009


I am on my way to make agps very useful, so I try to get information
about how to get my rough location.

The perfect way is the cellid you are in. You can get your location with
an aberration of about 3km so you can use it for agps without problems.
Another interesting fact is, that you have it everytime automatically.

So how to get your location out of the cellid? One possibility is to get
it from projects like cellhunter or opencellid or something. But whats
about areas no has ever been?

So I looked out for an alternative way. I live in germany so all about I
am trying to do is working in germany and may be transferred to other
countries, too. We have only 4 mobile phone carriers here in germany.

O2 customers can get the location of the connected cell by using
cellbroadcasting. So O2 customers have no problems. The data is
broadcasted in the Gauß-Krüger-Format so you have to decode it and can
use it.

Last weekend I discovered that t-mobile uses the telephone area code as
the mobile phone local area code (lac). So if you are in an area which
uses 0571 / XXXX the lac will be 57XX (in hex). When you get the rough
location for an area code then you can use it for agps, too.

Eplus seems not to have any system in their lac's. I guess its numbered
from north to south but this is not confirmed.

I do not have a vodafone card so I have no information about it yet.

After all O2 customers yould profit from the data for agps and when
there is a way to get coordinates from area codes, tmobile customers as
well. So we just have to code a rough location finder to get the most of

Why do I tell this all to you? I have some questions and perhaps you
have some ideas and suggestions.

1.) anyone knows a was to get the coordinates of area codes?
2.) anyone wants to try to code something in this direction?
3.) is anyone interested in a program that would give agps the needed
data (so perhaps when I get the time I will start coding :) )

That's all for now, I am very interested in your ideas.

Greetings, Sebastian

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