N-Times Trilateral Centroid Weighted Localization Algorithm of Wireless Sensor Networks

Localization technology based on received signal strength indication (RSSI) is a low cost and low complexity technology, and it is widely applied in distance-based localization of wireless sensor networks (WSNs). The error of existed localization technologies is great. This paper presents an N-times trilateral centroid weighted localization algorithm (NTCWLA), which reduces the error greatly. Considering the instability of RSSI, we use the weighted average of many RSSIs as an indicator of the current RSSI. To improve the accuracy we select n (n=3) reliable beacon nodes to increase the localization times. Then we calculate the distances between reliable beacon nodes and the mobile node using an empirical formula. This new algorithm locates the mobile node N times with the trilateral centroid algorithm. Finally, we take the weighted average of the filtered reference coordinates as the mobile node´s coordinates. We experiment with the STM32W108 chip, which supports the IEEE802.15.4 protocol. Our experimental results indicate that this new algorithm is more accurate than the trilateral centroid algorithm.