Sensor Node Localization Using Mobile Acoustic Beacons
Node localization, also known as self-localization, is the problem of localizing physical sensor nodes in a given sensor network deployment. Localization is an essential tool for the deployment of low-cost sensor networks for use in location-aware applications and ubiquitous networking. In this thesis, we present a mobile acoustic beacon based sensor node localization method. Our technique is passive in that the sensor nodes themselves do not need to generate an acoustic signal for ranging. This saves cost, energy and provides stealthy operation. The acoustic ranging method used in this work provides longer range and higher accuracy. The mobile beacon can generate much more acoustic energy than a severely resource constrained sensor node, thereby significantly increasing the range. The localization algorithm is especially designed to work in reverberant environment such as dense urban terrain. The presented algorithm handles non-Gaussian ranging errors caused by echoes. Node locations are computed centrally by solving a global non-linear optimization problem in an iterative and incremental fashion.