Innovative Hybrid NAV/COM Solution for Improving Accuracy and Availability of User Positioning

The evolution of digital Global Positioning System (GSP) receivers jointly to the development of positioning applications is driving the technology toward the integration among cellular handsets and GPS chipsets [1]. In addition, due to the fact that the GPS accuracy is considered sufficient for civil Location Based Services (LBS), different studies have been started with the goal to face to typical problems experienced by Global Navigation Satellite Systems (GNSS): availability (in both urban and indoor environments [4]), start-up time, power consumption. In this light, NAV/COM integration between GNSS and communication systems is a possible solution for the overall performance improving. In this work results relative to an innovative hybrid NAV/COM system developed by Telecom Italia LAB (TILAB) with the support of Politecnico di Torino are presented. In such a strategy, the available GPS measurements are integrated with terrestrial positioning information. The main goal of this activity is to practically prove the improvements of a hybrid technique with respect to stand-alone GPS or pure cellular positioning strategies.