The Research Of Three-dimensional Positioning Technology Base On RFID

As wireless technology,mobile equipment and Intelligent device unceasing being researched and developed,indoor positioning technology has got more and more attentions.Radio frequency identification technology as a non-contact automatic identification technology,has achieved a wide range of applications in the item management,warehousing,logistics,personnel tracking,and other fields.How to use RFID system positioning,and obtaining the target object information about themselves at the same time have good research value and broad market prospect.As indoor electromagnetic environment is complicated,so choose the appropriate RFID positioning method is very important.At present,the more mature indoor positioning methods mainly including triangulation method such as TOA/TDOA,AOA,etc,and the scene perception method such as The reference node method,location fingerprinting method and rule modeling method and so on.But the above locating methods under the environment of dense tags are not ideal.On the three-dimensional indoor positioning technology under the condition of intensive tags,this thesis? s main work includes the following aspects:Firstly,Positioning method mainly includes three parts.For length,by improving the reference tag method,the dynamic reference tag method is put forward for the first time.By selecting the known location of the tag as a reference tag,it reduce the cost of deployment reference tags,and by introducing the concept of time stamp,it position the length between direction tag and reference distance,it also reduce the accumulated error.For height,through the analysis of the factors such as the antenna direction,polarization direction and power gain,the antenna?s dynamic grouping method is proposed.Based on the height distribution of label in environment,the antennas are grouped,and by counting and comparing the readers for each groups it generate the high positioning method.For depth,based on the rules modeling method,through self-learning of environment,the environment attenuating tendency is formed to determine the difference depth for the biggest RSSI ?s distribution area,and to locate the target tag in depth.Secondly,for the implementation process,it is similar position fingerprint method,mainly divided into environmental training stages and orientation stages.But in training phase,it not form the fingerprint for each specified point by measuring the RSSI,but generate high positioning method and the depth of RSSI attenuation law through the specimen collection and self learning environment.In positioning stage,by scanning the overall data,according to the method generated in environmental training phase,target labels respectively.Once positioning method is formed,in the same case of scenario remains,usually do not require multiple environment training.Finally,based on the positioning method proposed in this paper,the hardware environment in bank vault was lay out,the overall implementation process of three-dimensional positioning method under the environment of actual bank vault was described.And according to analyzing the results of Treasury's purse positioning system,the method proposed in this paper has has been proved to have high positioning accuracy and positioning accuracy.