GSM mobile positioning using kalman filter for sector antennas

Location based service becomes an emerging market due to technological advances achieved both at GSM phone operators and the multimedia nature of the mobile handsets. This paper investigates a new methodology of mobile positioning using only GSM network and integrating sectorial antenna information. The methodology employs an extended Kalman filter approach in which the stochastic errors related to various measurements are appropriately characterized and modeled. The developed approach relies on the knowledge of the base station locations as well as antenna polarization. Besides, radio propagation model like Hata-Okumura model was used for distance determination through signal strength information. A feasibility experiment was carried out in Birmingham area. An accuracy of less than 100 meters has been achieved, which shows substantial increase over standard timing advance related techniques and the commercial software.