WSN06-6: Performance Evaluation of Localization by Acoustic DS-CDM Signals

The authors have proposed a beacon signal radiation system from the power-line for time synchronization among wireless and wired nodes. The considered application of the radiation system is an indoor fine-grained localization. Our rangefinder uses direct-sequence code division multiplexed (DS-CDM) audible sound signals. This technique significantly improves performance in obstructed and noisy environments because of the spreading gain. In this paper, it is shown that the obtained average and worst accuracy of the localization in a 4 m² plane is 1cm and 4cm, respectively, if there is no obstacle. Even if there are obstacles, the proposing method is possible to measure the location by the diffracted sound wave. If the obstacle is relatively small, its accuracy is within 5cm. On the other hand, if the obstacle is relatively large, a method to determine the presence of the large obstacle is proposed. These results are shown experimentally.