A Decentralized Approach to Sound Source Localization With Sensor Networks

Abstract

A sound source localization system has been developed based on a fully decentralized sensor network. Decentralization permits all nodes in a network to handle their own processing and decision-making, and as a result, reduce network congestion and the need for a centralized processor. The system consists of an array of battery operated COTS Ethernet-ready embedded systems with an attached microphone circuit. The localization solution requires groups of at least four nodes to be active within the array to return an acceptable two-dimensional result. Sensor nodes, positioned randomly over a 10 square meter area, recorded detection times of impulsive sources with microsecond resolution. In order to achieve a scalable system, nodes were organized in groups of from 4 to 10 nodes. Grouping was determined by the selecting the nodes farthest apart from each other. A designated leader of each group analyzed the sound source arrival times and calculated the sound source location based on time-differences of arrival. Experimental results show that this approach to sound source localization can achieve accuracies of about 30 centimeters. Perhaps more importantly though, it is accomplished in a decentralized manner, which can lead to a more flexible, scalable distributed sensor network.