Today's pervasive collaboration environments, together with the recent technical enhancements of sensing technologies have boosted the development of a new branch of online services whose functionalities are based on their users' physical position. Many new services are being planned which conveniently exploit the knowledge of users' location, determined thanks to the mobile devices (e.g. cell phones) users carry on them. Specifically, geo-location of mobile terminals relies on the cellular network infrastructure and protocols to provide a reliable and accurate estimate of mobile terminals position, without the need of global positioning systems, such as GPS. In this paper, we present a novel lookup table correlation technique for geolocation, with multiple position estimation and optimal location techniques. Our approach provides high precision in location and tracking, thanks to the usage of advanced propagation models for mobile radio networks design, and to the querying of GIS (Geographical Information Systems), in conjunction with Kalman predictive filtering.