Closely Spaced Paths Effect Mitigation for Indoor Location Systems

Paper presents a proposal of method for closely spaced paths mitigation for indoor location system based on spread spectrum signals. At the beginning issue of closely spaced paths influence for the accuracy of TO A determination is explained. In the following part results of indoor propagation simulations are presented. These simulations show relationship between delays and directions of arrival of power delay profile components. The proposal of simple four-element null steering antenna array, which can mitigate this effect, is proposed. The paper contains also results of measurements showing influence of multipath propagation to coarse code synchronization.