Localization of Sound Sensor Wireless Network with a Mobile Beacon

Abstract

Most of wireless sensor network (WSN) applications need the sensor nodes aware of their own locations.In this paper, we adopt a mobile beacon node to construct sensor node localization scheme in a randomly deployed wireless sensor network (WSN).Supposing that each sensor node have one omnidirectional antenna and one microphone, the mobile beacon node fits with two directional antennas and two directional sound sources orienting to the horizontal axis and the inverse respectively.In the proposed scheme, we adopt a multi-modal approach combining radio and sound.The mobile beacon node determines its coordinate via GPS, broadcasts time labels and its coordinate information, and emits sound pulse at the same time as it travels through the WSN.The sensor nodes detect these beacon messages and sound pulses, measure the time delays between radio and sound pulse, then adopt the y-coodinate of the beacon message of the minimum time delay between radio and sound pulse as its own and obtain the x-coodinate according to the beacon node antennas'ID.Our approach can accurately estimate the sensors" locations.It is displayed that the localization scheme, designated as DAS, is robust to various parameters of the WSN and immune to obstacle surroundings through error analysis and computer simulation.