GSM localization - triangulation

Hi !

Am making one small project with my sim900 module and AT command set. The goal is to get , as much as possible, correct location of my gsm modem. This is what i tried so far:

AT+COPS?

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+COPS: 0,0,"Tele2" OK

AT+CREG?

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+CREG: 0,1 OK

Parameters: 0 - automatic choice (the parameter will be ignored) 1 - alphanumeric short form

AT+CGREG?

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+CGREG: 2,1,"006F","263F"

Am getting good location but just one line and one tower...

AT+CGREG =?

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+CGREG: (0,1,2) OK

What does this 3 parameters do ? Should there not be just two ? How can i call AT+CGREG[=[]] with this "n" number.

Anyway, help needed :-) on setting basic triangulation.

Thank you in advance ! GM