The Research Of An Improved APIT Localization For Wireless Sensor Network

The basic task of wireless sensor networks is to obtain valuable information ofthe physical world accurately. However， there are many restrictions such ascalculation，storage，reliability of wireless communications and network bandwidth inwireless sensor networks.It is very import to investigate the high efficiency of sensornodes，locatiozation of low energy consumers of wireless sensor networks.The key technologies in wireless sensor networks include networkcommunication protocol， core supporting technology， self-organization andmanagement and application technology. Node localization is one of key technologiesto support wireless sensor networks. The precise node location is the premise that notonly determines the position of some events and targets in the net，but also deals withtarget recognition，monitoring，navigation，and so on in many applications.Moreover，it is the basis of numerous links such as node cover，routing protocols， networktopology control.It is the prerequisites to wireless sensor networks working highlyquality.The network seamless coordination and interaetion with the physical world arerealized by localization technology.Without it，everything else is pointless.This paper analyzes deeply on APIT localization algorithm.Then we introduce itsimproved algorithm which we called WTC-APIT，to promote the precision of APIT.APIT can achieve higher precision position estimation with small communication cost.However, in the process of APIT test, boundary effect and low neighbor node densitycan easily increase InToOut error and OutToIn error. Otherwise, the grid scanalgorithm is inefficient and has a lower fault-tolerance to OutToIn error. In allusion tothe problems mentioned above, an improved Weight Triangle Centroid APITalgorithm based on RSSI is proposed. Simulation results show that the improvedalgorithm has a higher fault-tolerance to OutToIn error and can enhance the efficiencyof algorithm.We use C++and MATLAB to emulate WTC-APIT and compare it to APITdifferently under the different anchor ratios，different conununication radius of nodesand the same anchor ratio.The result sufficiently shows that WTC-APIT promoteslocalization precision in real applications.