Location API Implementation Information

[molp]

Hello,

I have a question concerning the implementation of the location API on cell phones. From what I've read so far, if there are no GPS satellites available, the implementation should switch to calculating the position with cellIds.
How is this done? Is just one basestation used or a couple of them to do some kind of triangulation? Does the basestation send coordinate information or does the implementation look up the coordinates in some table that converts cellIDs to coordinates? Does it need a GPRS connection to do this?
Where can I get more (detailed) information on this topic? I couldn't find much about this, I would really appreciate any pointers in this direction!

[symbianyucca]

Basically if you are using Symbian C++ and the LSB APIs, you do not need to know how the location is aquired, you just use the same interface for querying the location, and let the LBS framework handle the actual positioning.

[nokia_e70]

Basically if you are using Symbian C++ and the LSB APIs, you do not need to know how the location is aquired, you just use the same interface for querying the location, and let the LBS framework handle the actual positioning.

Does this actually work, or it's just the API ? I recall seeing a table which listed implementation of various features on different versions of S60. The table informs that the number of S60 versions that have GSM based positioning implemented is None.

[symbianyucca]

Dunno what it is, but at least me N95 lists position methods as
1. Bluetooth GPS
2. Assisted GPS
3. Integrated GPS
4. Network based

So I quess it depends on the netowork, if they do offer cell based positioning.

[nokia_e70]

4. Network based

So I quess it depends on the netowork, if they do offer cell based positioning.

And I think that this is a purely theoretical construct. It would make sense if there would be provision to include a 3rd party backend library that does this, based on the data from the phone's radio transmitter. But as this data is inaccessible, and S60 isn't quite the only platform on the market, network ops will choose to implement solutions that work everywhere (Sim toolkit).