Wireless Sensor Networks Based On The Trilateral Gas Source Localization Algorithm Research

A Wireless Sensor Network (WSN) comprises of a collection of sensor nodes performing sensing and communication tasks and these with special-purpose nodes which are able to collect and aggregate sensor data and then send it to a central base station. Wireless sensor network provides great opportunities for the development of military and commercial applications. One of the important applications is "source localization and tracking". The study for node localization of wireless sensor networks possesses great significance not only in the theory but also in practice, and it tends to be an essential part in the plume source research area.In this thesis, WSN localization algorithms were researched and the main works were deployed as follows:Firstly, the thesis discussed the necessity of this research starting from background and significance of WSN. Besides, some issues concerning the research were investigated and discussed respectively, for instance, its current research situation at home and abroad, characteristics, sensor nodes composition, WSN architecture and its key application areas.Secondly, the basic positioning principle and realization issues were explained. In accordance with the standard classification of range-based and range-free technology, a set of common ranging techniques were expounded in the paper. Focused on discussing and analyzing a few classical rang-free localization algorithms, it introduced the impact of algorithm evaluation indicators on localization performance.After that, taking the investigation of trilateral localization algorithm as a core, this thesis analyzed several typical trilateral algorithms in detail, and discussed the principle and procedures of DT, CT, WCT and ETDT algorithms. What's more important is that, it proposed an effective source localization algorithm called Equilateral Triangular Distribution Trilateration algorithm (ETDT) which can be applied to Wireless Sensor Network system. Considering the nodes' distribution impact on localization error, beacon nodes were deployed in equilateral triangle. ETDT combined Trilateration measurement with Weighted Centroid method, and adopted angular weighted function to reduce the localization error, which improved its localization performance at the same time.To the actual situation for the paper, it used Matlab for algorithm simulation in the paper, and analyzed a large number of simulation experiments based on the chosen model. It applied concentration attenuation model of the plume to estimate the source position in static environment, the position of the source was obtained by calculating the centroid of weighted polygon. Effects of average localization errors were also analyzed using DT, CT, WCT and ETDT algorithms when varying the distance of sensor nodes and the strength of background noise in different scenarios. Moreover, a group of simulation experiments proved its validity on location accuracy compared with other similar algorithms.Finally, this thesis was concluded.