An Indoor Multi-tag Cooperative Localization Algorithm Research Based On NMDS

With the rapid development of Internet of Things(IoT)technology,indoor positioning technology has been widely concerned by domestic and foreign experts and scholars.Positioning technology has a very wide range of applications,the common areas of indoor positioning application include home use,military,medical,rescue and so on.At present,outdoor positioning technology has been developed relatively mature,such as the common GPS,BeiDou positioning system.Due to the closeness and complexity of the indoor environment,the signal such as GPS becomes relatively weak in the room and can not meet the accuracy requirement of indoor positioning.So how to achieve high-precision positioning in the indoor environment has become a research hotspot.Because RFID has the advantages of fast read and write speed,easy deployment and small tag size,low price and other advantages make indoor RFID positioning technology gradually popular.At the same time,the cheapness of tags has made it more popular in multi-tag applications in the Internet of Things.Due to the lack of communication between the RFID tags,most of the traditional indoor RFID positioning algorithms can only locate one tag at a time and can not achieve multi-tag positioning at the same time.In order to solve this problem,this dissertation proposes an indoor RFID multi-tag cooperative positioning algorithm based on non-metric multidimensional scale named NMDS-RFID(F).NMDS-RFID(F)algorithm is divided into the following three steps: First,using the received signal strength(RSS)Euclidean distance between the tags to get the rank order relationship of the distance for all pairs of tags;And then use the non-metric multidimensional scaling(NMDS)algorithm to obtain the relative coordinates of the tags.Finally,because the coordinates of the reference tags are known,the absolute coordinate of the tags is obtained by using the coordinate system transformation algorithm.The proposed localization algorithm is validated by building an indoor simulation environment.The simulation results show that the localization performance of NMDS-RFID(F)algorithm is better than that of RFID fingerprint localization algorithm.