Research On Localization Algorithm Of Wireless Sensor Network Based On RSSI And APIT

In recent years, wireless sensor networks is one of the hottest research projects. It can be widely applied in many fields such as smart home, industrial automation, livestock tracking, national defense and military, coal mine personnel tracking, environmental monitoring and space exploration and so on. In the studying of wireless sensor network that is a new access to information and processing mode, some basic questions including:node localization, network communication protocols, network security, data integration, network layout, time synchronization and embedded operating system and so on. Among them, node localization is one of the most important aspects in wireless sensor networks.Node location information is not only premise of the location of monitoring events or gain other important information,but also it is the foundation of improving the efficiency of routing, offer network coverage quality and network topology configuration function to managers, if there is no location information of the events,there is no any significance. The resources and energy of sensor network nodes are limited, which makes the localization of nodes is very difficult. The diversity of sensor networks also determines that there is no universal location algorithm that is suitable for a variety of network environments. In wireless sensor networks, localization algorithm can be divided into Range-based localization algorithm and Range-free localization algorithm, localization algorithm of Range-based can achieve more accurate positioning, but the hardware requirements higher, and localization algorithm of Range-free on the hardware requirements are not high, but positioning accuracy is less. By means of the combination of two kinds of localization algorithm, this paper try to achieve the objective of higher positioning accuracy and better performance.First of all, this paper expounds the research significance, the domestic and foreign research status quo, and the specific application domain of wireless sensor network positioning system, and analyze the basic the characteristics, system structure, protocol stack and key technologies involved in wireless sensor networks.Secondly, on the basis of analyzing the basic principles of wireless sensor network positioning algorithm, this paper discusses the classification and performance evaluation criteria of localization algorithm of wireless sensor networks.Then, the deficiency of the original algorithm of APIT are analyzed, aiming at the inherent defects of the algorithm, different improvement measures are put forward according to different situation. According to the idea that the introduction of a two-point positioning method and upgrading the blind node that have been positioned for beacon node, a new improved algorithm is put forward. And the blind node positioned is modified, so as to increase the positioning accuracy and coverage rate of the algorithm. The reliability and accuracy of the algorithm are verified by the simulation experiment on Matlab.Finally, on the basis of the RAPIT algorithm, a better positioning algorithm is proposed as MAPIT algorithm, the basic ideas of the algorithm is based on the mobile beacon node localization, so as to improve the positioning performance of blind nodes. In addition, the positioning accuracy of the algorithm is modified according to the method of distance measurement of RSSI. And then, this paper makes the simulation experiments to the original APIT algorithm and RAPIT algorithm and the improved MAPIT algorithm, the performance of three kinds of the algorithms are analyzed in detail based on node density, density of beacon node, the node communication radius. The simulation results show that the comprehensive performance of the MAPIT algorithm is greatly improved.