Localization in time and space for wireless sensor networks: A Mobile Beacon approach

Localization in time and space can be defined as the problem of solving both synchronization and positioning problems at the same time. This is a key problem for wireless sensor networks that need to determine the timing and location information of detected phenomena, especially for tracking applications. In this paper, we discuss the relationship between these two problems and propose the Mobilis (Mobile Beacon for Localization and Synchronization) algorithm, a new time-space localization algorithm for wireless sensor networks. The main aspect of the Mobilis algorithm is the use of a mobile beacon for both localization and synchronization. A mobile beacon is a node that is aware of its time and position (e.g. equipped with a GPS receiver) and that has the ability to move around the sensor field. In our algorithm, the synchronization component uses the packets required by the positioning component to improve its performance. Similarly, the positioning component benefits from the communication required by the synchronization component to decrease errors. We also present an extensive set of experiments and simulations to evaluate the performance of our algorithm.