Mobile phone tracking is a process for identifying the location of a mobile phone, whether stationary or moving. Localization may be effected by a number of technologies, such as using multilateration of radio signals between (several) cell towers of the network and the phone, or simply using GPS.
To locate a
mobile phone using multilateration of radio signals, it must emit at least the
idle signal to contact the next nearby antenna tower, but the process does not
require an active call. The Global System for Mobile Communications (GSM)
is based on the phone's signal strength to nearby
antenna masts.