The Mobile Position Center (MPC) is a central component in the position determination ofmobile devices in GSM networks. In general, position determination in mobile networks
is based on various methods with time-of-arrival measurements.Time of Arrival (ToA) is one time-based method for position determination, Time Difference of Arrival (TDoA) is another. In the latter, the propagation time differences of several time stamps that the radio signals of a mobile device have to different base stations of the mobile network are recorded and evaluated. Another time-based method is Roundtrip Time of Flight
(RToF), in which the Mobile Position Center evaluates the travel times and travel time differences between the mobile device and the base stations, compares them, and uses them to calculate the location of the mobile device.