Localization systems for wireless sensor networks

Monitoring applications define an important class of applications used in wireless sensor networks. In these applications the network perceives the environment and searches for event occurrences (phenomena) by sensing different physical properties, such as temperature, humidity, pressure, ambient light, movement, and presence (for target tracking). In such cases the location information of both phenomena and nodes is usually required for tracking and correlation purposes. In this work we summarize most of the concepts related to localization systems for WSNs as well as how to localize the nodes in these networks (which allows the localization of phenomena). By dividing the localization systems into three distinct components-distance/angle estimation, position computation, and localization algorithm-besides providing a didactic viewpoint, we show that these components can be seen as subareas of the localization problem that need to be analyzed and studied separately.