DETERMINING THE CHANGE IN TIME AT A MOBILE TERMINAL

摘要

I n a terminal 106 having a receiver 202 for receiving the signals from plural transmission sources 101 - 105 whose positions and transmission time offsets are unknown within the terminal, a method is provided for determining the change in the time (elapsed time) at the terminal between two instants. A t a first position of the terminal a first set of measurements, aligned to a first instant, of a signal parameter representative of the time or phase of receipt of said signals from said plural transmi ssion sources relative to one or more of them, or to a reference, or to a terminal clock is obtained. Then at a second position of the terminal a corresponding second set of measurements, aligned to a second instant, of a signal parameter representative of the time or phase of receipt of said signals from said plural transmission sources relative to one or more of them, or to the reference, or to the terminal clock is also obtained. The aligned measurements of the first and second sets are combined, and th e time elapsed between the first and second instants is calculated from the change in the combined aligned measurements of the first and second sets.