Има такова нещо ... не е само слух

TIMING ADVANCE

The Timing Advance is used to compensate for the time it takes a RF signal to go at the speed of light between the BTS and MS. The maximum BTS radius of 35 Km is divided into 64 TA steps ( This means 547 meters / TA step - As a simplification 550 meters will be used) .TA multiplied with 550 meters will give the minimum distance to the BTS. The maximum distance will be (TA +1). A TA value will pinpoint a BTS to a circular band 550 meters wide, with an inner radius of (TA x 550) meters. This can be used to triangulate the position of a BTS by having 2 -3 readings at different positions.

Timing Advance Distance to BTS
0 --------------- <550 m
1 --------------- 550 m-1100 m
2 --------------- 1100 m-1650 m
3 --------------- 1650 m-2200 m
4 --------------- 2200 m-2750 m
5 --------------- 2750 m-3300 m
...
...
...
63 -------------- 35 Km

Доста оператори по света предлагат LBS (Location Base Services) работещи по този метод, но има и други.


В друга тема мернах че питаш какво означава A-GPS (Assisted-GPS) повече инфо има тук

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