LRD: A distributed and accurate localization technique for wireless sensors networks

Today, cheap, smart sensors, networked through wireless links and deployed in large numbers, provide unprecedented opportunities for monitoring and controlling homes, cities and the environment. In addition networked sensors have a broad spectrum of applications. Localization capability is essential in most wireless sensor networks applications. In environmental monitoring applications such as animal habitat monitoring, bush fire surveillance, water quality monitoring and precision agriculture, the measurement data are meaningless without an accurate knowledge of the location from where the data are obtained. Localization techniques are used to determine the location information by estimating location of a sensor node. It is well known that distance measurement errors affect the accuracy of estimated location. These errors may be due to methodical or environmental factors. Trilateration is a well-known method use to localize nodes when we have the distance to three anchor nodes. But trilateration performs poorly when the distance measurement errors are high. We proposed a new algorithm LRD (Localization with Ratio-Distance) which performs finely even when the measurement errors associated with the estimated distance to anchor nodes are high. In addition to accuracy our algorithm, LRD has the advantage to be easier to implement than trilateration. Our algorithm is easier because first, we don't need the center of surface computation that adds a heavy many computation steps to trilateration and second because LRD finds node position with the intersection of only two circles while trilateration needs three circles.