Improving subscriber position location using a hybrid satellite-assisted and network-based technique

The ability to locate the position of mobile terminals is emerging as a key facility to be provided by cellular network operators to their customers. There is already an important number of services enabled when position location support is present in the network, such as emergency-call assistance, fleet management location-based value added and multimedia services, navigation, stolen vehicle monitoring, improved network management and differential billing. Many manufacturers have already developed positioning methods, still none of them has been adopted in a cellular networking environment. A novel, hybrid technique for position location is presented and its performance and compliance with the related standards is evaluated. The proposed technique is based on two well-established methods, one being a centralized differential GPS method, where corrections are applied to the positions reported by the terminals' receivers, the other one being network-based positioning method based on the time difference of arrival (TDOA) technique.