Research On Indoor Location Algorithm Based On RFID Technology

With the progress of science and the development of society,the demand for positioning services of people is higher gradually.And indoor positioning becomes more and more important to people's daily lives.Indoor positioning is widely applied in many fields,such as large-scale logistics management,personnel location testing in underground coal mine,the safety of the elderly in the nursing institution and property management of large supermarket.As a wireless communication technology,RFID(Radio Frequency Identification)shows excellent performance and gradually becomes an important way of indoor location.RFID technology through the radio wave to identify the target object and read tag's data,with non-line of sight,non-contact,anti-interference and so on.Firstly,in this paper,the research background and significance of indoor positioning is introduced,and the composition and working principle of the RFID system,communication protocol and other related theories are described.This paper analyzes the principles,advantages and disadvantages of RFID related algorithms.Then,the LANDMARC algorithm and VIRE algorithm based on RSSI localization technology are studied.This paper analyzes the important factors such as label density,the number of nearest neighbor labels,the threshold size,the number of virtual tags by the experiment and summarizes the shortcomings of the two algorithms.The VIRE algorithm has been improved from two different perspectives.Aiming at the problem that the nearest neighbor reference label is not accurate and the positioning accuracy is insufficient in VIRE algorithm.In order to calculate the coordinates of tag,we improved the algorithm by using the segmented Lagrange interpolation method to calculate the signal strength of the virtual tag,adapting dynamic threshold to filter the adjacent label and using the deviation of the adjacent label to correct the positioning coordinates.The experimental results show that the average positioning accuracy of the VIRE algorithm is 0.5165 m,and the average positioning accuracy of the improved algorithm is 0.1502 m.Compared with the VIRE algorithm and the Lagrangian interpolation VIRE algorithm,the positioning error is obviously reduced and the positioning stability is improved.Aiming at the problem that the dynamic adaptability of VIRE algorithm is poor,an algorithm with dynamic feedback environment parameters is proposed.The improved algorithm is used to adjust the structure of the reader and the reference tag,and the positioning sub-region division method is used to narrow the positioning range and improve the positioning real-time.The environment parameters n and ? in the logarithmic path loss model are dynamically modified.The improved algorithm uses the non-interpolation method to compute the virtual tag RSSI value.The improved algorithm uses the non-interpolation method to compute the virtual tag RSSI value.Finally,the nearest neighbor reference label is optimized by the deviation correction method.The experimental results show that the improved algorithm is suitable for localization environment with local dynamic change and the average positioning accuracy is about 0.1579 m.The simulation results show that the accuracy and stability of the two improved algorithms are improved compared with the LANDMRC algorithm,VIRE algorithm and Lagrangian interpolation VIRE algorithm.