Patent ID: 8050687

Claim:
A method of calculating the unknown position or state of motion of a mobile terminal, wherein said mobile terminal is one of at least two terminals, each of said at least two terminals having a receiver for receiving signals from base transceiver stations, and in which the relative timing offsets of signals from said base transceiver stations received by said at least two terminals are used in a determination of the location of said mobile terminal, said base transceiver stations having known directional transmission patterns, and the method comprising: estimating, at said mobile terminal, a bearing or bearings respectively of one or more of said base transceiver stations from said mobile terminal, and assigning weights to measurements of at least some of the relative timing offsets of the received signals made by said mobile terminal and using said weighted measurements in accordance with their weighting for said determination of the position or state of motion of said mobile terminal using the relative timing offsets of signals from said base transceiver stations received by said at least two terminals, said weights being calculated from said bearing or bearings and the known directional transmission pattern of the or each of said base transceiver stations.