Research On Indoor Location Algorithm Based On RFID

Location information is one of the basic elements for smart city and cyber-physical system.Radio frequency identification(RFID)as a non-contact automatic identification technology has been widely used in asset management,personnel tracking,logistics and other fields.Localization of the tagged item,obtaining both the ID and the position,has significant value and wide application foreground.Localization of the passive RFID tags is hard to achieve in the indoor environment for the complex environment,multipath propagation and noise.Therefore,studying the RFID localization method is important.Using RFID based location awareness technology to locating the tagged object or human is regarded as a significant solution to provide the accuracy location information of the indoor "last one meter".In RFID systems,how to detect the position precisely is an important and challenging research topic.In this paper,we propose a range-free 2D tag localization method based on phased array antenna,called as PATL.This method takes the advantage of the adjustable radiation angle of the phased array antenna to scan the surveillance region in turns.By using the statistics of the tags' number in different antenna beam directions,a weighting algorithm is used to calculate the position of the tag.This method can be applied to real-time location of multiple targets without usage of any reference tags or additional readers.Additionally,we present an optimized weighting method based on RSSI to increase the locating accuracy.We use a Commercial Off-the-Shelf(COTS)UHF RFID reader which is integrated with a phased array antenna to evaluate our method.The experiment results from an indoor office environment demonstrate the average distance error of the PATL is about 21cm and the optimized approach achieves an accuracy of 13cm.This novel 2D localization scheme is a simple,yet promising,solution that is especially applicable to the smart shelf visualized management in storage or retail area.