The Research On Localization Technology Of Wireless Sensor Network

With the rapid development of Internet of things technology, the Wireless sensor network as an important part has been widely concerned and becomes a research focus in recent years in many research institutions. Wireless sensor network is composed of a large number of low-cost wireless sensor nodes. Nodes get the ability of sensing, data storage and data processing through wireless communication technology, then send the result to the terminal processor.Nodes location information is the indispensable part in the wireless sensor network messages. It is an essential prerequisite for target detection and tracking, event location reporting, and other functions. In view of the sensor nodes energy limited, vulnerable to environmental impacts, large numbers and random characteristics of spreading, presenting an efficient and accurate localization algorithm is very important.Now whether based on distance measurement, localization algorithms are divided into two classes:based on range localization algorithms and based on range-free localization algorithms. Algorithms based on distance measurement mean measurement of angle and distance between nodes, then get the unknown nodes coordinate through the trilateral measurement method or triangulation method, such as RSSI, TDOA, AOA. The Range-free localization algorithms build polygon to get centroid or get unknown nodes position from the relationship between hop and distance. The Range-free algorithms include the centroid algorithm, DV-hop, Amorphous, etc. Among various kinds of algorithms, the centroid algorithm is simple, range-free, easy to implement and completely dependent on the network connectivity. The higher density and the more uniformity of nodes deployed, it could get the more accurate positioning results. The opposite error is bigger. In the light of the features of the centroid algorithm, many experts put forward improvement methods.Among all the classical localization algorithms, Amorphous is one of the Range-free localization algorithms, by which unknown nodes acquire anchors’ information within designated hops, and estimate the distances from anchors to themselves. In this paper, we analysis the disadvantages of Amorphous location algorithm and provide an improved localization algorithm model with hop number correct based on Centroid algorithm theory. The experiments shows that our algorithm can get good localization results.Among all the classical localization algorithms, Amorphous is one of the Range-free localization algorithms, by which unknown nodes acquire anchors’ information within designated hops, and estimate the distances from anchors to themselves. In this paper, we analysis the disadvantages of Amorphous location algorithm and provide an improved localization algorithm model with hop number correct based on Centroid algorithm theory. The experiments shows that our algorithm can get good localization results.In this paper, we present a centroid localization algorithm which based on time difference of arrival(TDOA).This localization process gives different weights of beacon nodes based on each time interval difference,then uses the centroid localization algorithm to locate object. The simulation results show that the algorithm can effectively improve the positioning accuracy of the unknown nodes.