passive localization using rotating anchor pairs in wireless sensor networks
Several range-free and range-based techniques have been proposed to solve the localization problem in wireless adhoc and sensor networks. Although range-based techniques are known to be more accurate than their range-free counterparts, they usually require nodes to be equipped with sophisticated hardware that makes these techniques inappropriate, especially under massive deployments, for the presumably inexpensive sensor nodes. From hardware prospective, it is much easier to obtain received signal strength(RSS) than to obtain angle of arrival(AOA) or time difference of arrival(TDOA). Hence, localization techniques based on RSS are undoubtedly the most acceptable in the literature. A major drawback with RSSI-based distance measurements is the inherent inaccuracy due to the irregularity of signal propagation in different directions. In this paper, we propose and evaluate, a new localization protocol for sensor networks where each sensor is localized based on its angle to at least two of the network anchors. Only angles are determined based on the relative strength of received signals and no distance measurements are needed which in turn reduces the impact of the irregularity of signal propagation on the localization accuracy. Although our protocol requires each sensor to be within the transmission range of only two anchors, it can be easily extended to benefit from the existence of all available anchors for a better localization accuracy. Simulation results under noise-free and noisy conditions show that our protocol achieves higher localization accuracy than other protocols which makes it useful for most WSN applications.
localization rotating anchors wireless sensor network wsn rssi