Published online by Cambridge University Press: 05 December 2014
The term “localization” in wireless sensor networks (WSNs) refers to determining the location of a device in the absence of additional infrastructure, such as satellites. As such the location discovery service enables a device to know its location. The use of additional devices is not suitable for wireless networks, especially the resource-constrained ones, because of the power-hungry nature of such devices. For example, the global positioning system (GPS) uses the distance measurements from satellites to calculate the location of a device. Additionally, GPS cannot be used in indoor localization. Traditionally, the localization problem has its origin in the field of robotics, where it is necessary to locate a robot. For navigation of a robot through a terrain, it is important to have the location information.
The information provided by wireless sensor networks (WSNs) is highly correlated with respect to space and time. In applications such as target tracking , geographic routing [2, 3], environmental monitoring , structural health monitoring , and forest fire monitoring , the location of information generating sensors is very important. As an example, in forest fire monitoring applications, the location of fire is required to be tracked in order to take preventive measures. Further applications include the optimization of medium access and improvement of location-based geographic routing protocols. However, being a network of small low-powered devices, the localization problem for WSNs is very different from other networks. Also, the localization of the nodes is important for tagging the sensor information with nodes’ location information.