CELLULAR RADIO LOCATION SYSTEM

摘要

The location of a mobile unit M of a cellular radio system is determined by determining the differences in timing of a characteristic feature of the transmission of the control channel of each base station A, B, C, D, E as measured at the mobile unit. Preferably the characteristic feature is the training sample already used by the mobile unit in cellular systems to measure signal strength in order to inform handover decisions. By determining the differences between time of arrival of transmissions from four base stations A, B, C, D, position in two dimensions can be derived without prior knowledge of the actual distance to any of the base stations. A fifth base station E allows position in three dimensions to be determined.