Research On RSSI-oriented Three-dimensional Weighed Centroid Localization In Wireless Sensor Networks

Wireless Sensor Network (WSN) is a self-organizing multi-hop network system which is usually composed of large numbers of micro-sensor nodes. Well known as an intelligent wireless communication technology after computer and internet, this technology has already aroused more and more attention. With the rapid development of engineering science, WSN is widely used in multiple fields such as national defense and military, environment monitoring, disaster relief and many other fields. To obtain the localization information of sensor nodes accurately is a key technology.This paper mainly studies 3D localization technology of sensor nodes in the wireless sensor networks. Though a large number of mature localization algorithms had been put forward for wireless sensor networks, most of them are restricted to two-dimensional space. However, the three-dimensional space is more down-to-earth in reality applications, such as waters and airspace. Therefore, proposing a proper localization algorithm in three-dimensional space has its important theoretical significance and practical value. Based on this situation, this paper focuses on research methods of the three-dimensional nodes localization and proposing the following algorithm.This paper briefly introduces the basic knowledge and technique of nodes localization in wireless sensor networks. The research status and development trends are also concerned. This paper also discusses evaluation indicator of the nodes localization algorithms in wireless sensor networks. After discussing the theory of distance measurement by received signal strength indication(RSSI) and the wireless signal attenuation model, this thesis gives a detailed analysis of the main factors affecting the accuracy of the model and then uses existing hardware systems to calibrate parameters of the model in different kinds of environments such as in the building and the open country. This paper also analyses the relationship between receiving sensitivity and communication radius of sensor nodes.Aiming at nodes localization in three-dimensional space, this paper proposes two different RSSI-oriented three-dimensional weighed centroid localization(RWC-3D) algorithms according to different kinds of environment. The first algorithm has a very limited spending of communication and computation while the second one has a certain degree of calculation. The simulation results show that the proposing RWC-3D algorithms have high localization precision, reliability and wide applications. This paper also analyses the effects of relative parameters in the attenuation model and the communication radius of sensor nodes on localization precision.Then, on the basis of the proposing RWC-3D algorithms, this paper adds two different kinds of revisions to the RWC-3D algorithms, including the alteration of communication radius and the movement of the blind nodes. It is shown by the simulation experiments that the revisions of the algorithms have further enhanced the localization precision and reliability.Therefore, the proposing algorithms and revisions have positive implications for research on 3D localization technology of sensor nodes in the wireless sensor networks.