Application of Directional Antennas in RF-Based Indoor Localization Systems

A simple technique to estimate the position of a given mobile source inside a building is based on the received signal strength. For this methodology to have a reasonable accuracy, radio visibility of the mobile node by at least three access points is required. To reduce the number of required access points and therefore, to simplify the underlying coverage design problem, a new scheme is presented that takes into account the distribution of RF energy around the receiver. In other words, it is assumed that the receiver is equipped with a circular antenna with beamforming capability. In this way, the spatial spectrum of the received power can be measured by rotating the antenna beam around the 360-degree field of view. This spatial spectrum can be used by the receiver as a means for estimating the position of a mobile transmitter. In this thesis, the feasibility of this methodology is investigated, and the improvement achieved in the positioning accuracy is shown.