A new network-based positioning method for location services in 2G and 3G mobile communications

Location-based services are a new class of services, where the service offering for a mobile user is tailored to his actual geographical position. Examples include location-based billing, new information services giving e.g. information on nearby restaurants or gas stations, as well as a number of tracking and navigation services. All these services, need an estimate of the users position. The required accuracy of these estimates depends on the actual type of service. While billing and information applications tolerate positioning errors to some extent, the requested accuracy for tracking and navigation services is quite high. Therefore, the positioning technology needs to be chosen carefully in order to meet the requirements (see Drane, C. et al., IEEE Commun. Magazine, vol.36, no.4, p.46-59, 1998; Fischer, S. et al., Proc. IEEE 49th Vehicular Technology Conference - VTC 1999, vol.3, p.1962-6, 1999). We propose a new positioning method which is applicable to billing and information services, offering enhanced accuracy over existing methods without adding constraints to the mobile terminals. Though the test results presented here cover the application of this method to GSM, the algorithm is very generic and can be equally well applied to UMTS and other 3G technologies.