Indoor Localization System Design In Wireless Sensor Networks

In the context of rapid development in Internet,Internet of Things,Car networking,series of information related to people or things is becoming more and more concern and attention.Outdoor navigation and position has a very mature satellite technology,and in the complex indoor environment,due to the inability to use satellite signal,which prompted large of companies,colleges and universities to find new solutions.Indoor environment is diverse,variety,such as shopping malls,airports,hospital,office building,parking lot,and warehouse.In these part,more and more basic services base on localization are developed and applied such as person location,cargo management,message delivery,etc.Most of the current indoor positioning technology are used in wireless sensor network,which also produce a diverse phenomenon.It mainly include RFID,WiFi,Bluetooth,ZigBee,UWB and CSS technology,which divided into received signal strength indication and time of flight categories.RSSI localization generally have low power,low cost,flexible networking,transmit information and other advantages.RSSI based ranging is easily led to awesome accuracy which affected by shading,reflection,refraction in complicated environment.Time based positioning has the advantages of better accuracy,low power cost and anti-interference,but the network is not flexible enough,less transmission of information and so on.After comparing and analyzing kinds of positioning technology,this paper uses ZigBee and CSS scheme for indoor position research.The volatility of RSSI caused by distance estimation deviation is a problem in ZigBee localization.LQI-RSSI ranging algorithm is presented through the experimental study of link quality indication and RSSI.Then the standard particle swarm optimization algorithm is improved by the combination of trigonometric function,through the distance measurement experiment and positioning experiment shows ZigBee localization has a good effect in small area.The paper analyzes CSS signal system and its advantages,choose double-sided two-way ranging algorithm,particle filter and least squares localization algorithm for CSS localization,so that the design can effectively solve problem of time synchronization.Through the ranging and localization experiment,it is concluded that CSS localization scheme can achieve better accuracy in large area.This paper also introduces the multiple information fusion algorithm in indoor localization,and put forward a micro base station based using ZigBee,CSS combined with air pressure sensor.Finally the article describes the relative positioning of the Internet of Things,and use the scheme for a small-scale experiments,the result made preliminary progress.