Hybrid TOA–AOA Location Positioning Techniques in GSM Networks

摘要

Positioning algorithms and their implementation in mobile networks are being investigated in the literature due to their importance in location services. Nowadays, the need for superior accuracy has cast attention to hybrid positioning techniques. In this paper, we introduce a novel algorithm for the identification of NLOS propagation using both angle and time estimates, which leads to enhanced versions of the Time of Arrivals and Angle of Arrivals positioning methods. Furthermore, a novel GSM procedure for the implementation of the latter techniques is proposed. In contrast to specified network-based GSM solutions (U-TDOA), the proposed requires minimum modifications in the GSM Phase 2+ infrastructure and protocol stack, and therefore increases the upgrade flexibility and minimizes the implementation cost. The proposed GSM positioning procedure has been experimentally validated using a GSM emulator and the modified signalling messages given by a measurement tool of the emulator are exhibited. Finally, the enhanced cost functions are experimentally evaluated using several GSM-like, high-capacity simulation environments and the results have shown significant reduction of the location error compared to the conventional techniques.