Research On Indoor Positioning Algorithm Based RFID

With the development of economy and mobile communication and wireless technology, wireless location technology becomes a hot research topic, especially the indoor positioning technology. Infrared, ultrasonic, GPS and other traditional positioning technology can't meet people's demands due to its complex system or expensive price or inaccurate positioning. RFID(Radio Frequency Identification) is a non-contact automatic identification technology, which uses radio frequency signals identifies specific objectives, then read and write the information. Positioning technology based on RFID is low-cost, non-contact, non line-of-sight and high positioning accuracy, so it becames one of the top choices in the field of indoor location. But the indoor environment is not only complex and variable,but also has influence of the multipath effect and random noise, therefore, the study of indoor positioning system algorithm makes sence. This paper mainly studied the indoor location algorithm based on RFID system, main research works are as follows:First, this paper describes research background, research meaning and research current situationthe of indoor positioning system based on RFID technology. Indoor wireless location technology, the basic component of RFID positioning system, indoor wireless channel model, basic method of positioning, positioning performance evaluation standard and the factors that affect the accuracy of positioning are analyzed.Second, several typical RFID indoor localization algorithms are introduced, which included LANDMARC algorithm, VIRE algorithm and BVIRE algorithm. Those location algorithms all use scenario analysis method based on RSSI values.The factors influencing algorithm are analyzed in the simulations. On the basis of the analysis of their advantages and disadvantages, the weights of LANDMARC algorithm is improved, which use positioning error of neighboring reference tags to correct the location of the target coordinates, the simulation results show that the improved algorithm improve the positioning accuracy of positioning results and it is better than LANDMARC algorithm.Third, the improved algorithm based on BVIRE is proposed, which also based on RSSI values of scenario analysis methid, it uses moving anti-pulse-interfere median filtering method to offset the effect of indoor environment factors. When calculating the RSSI values of grid virtual reference tags, using the Newton interpolation method to replace the original linear interpolation method, on the other hand, small probability exclusion method is adopted by the choice of neighboring reference tags. When calculating the position coordinates of object using error correction methods in neighboring reference tags, eventually improve the positioning accuracy of the system.Fourth, the simulation analysis of the improved algorithm is proposed in this paper, and analyzes the influence of the virtual label different density, size threshold, the regression equation and the different interpolation on the positioning accuracy, and analyzes performance difference of four algorithms in all kinds of the performance evaluation standard. The simulation result shows the effectiveness of the algorithm suggested in this paper.