Research On Hybrid Indoor Positioning With RFID And Magnetic Field

With the rapid development of Internet technology and the improvement of people’s life,precise positioning and navigation systems are becoming an integral part of people’s lives, which provide convenient services for the user. The indoor positioning technology based on fingerprint attracts the attentions from many researchers. RFID(Radio Frequency Identification) technology is more attractive in traditional method of indoor positioning technology,due to its high accuracy,adaptability,low cost and easy deployed to different environment.However,because of the wireless signal propagation is vulnerable to Reflection, refraction, multipath effects,etc in complex indoor environment,it limits the applications in practice.A single positioning technology is difficult to meet accuracy needs of indoor positioning, requiring a combination of different positioning technologies.The study shows that a unique and stable magnetic field is formed in reinforced concrete building.Particle filter based on magnetic field is one of the most popular method due to the high accuracy, but one potential problem is the heavy computation,The thesis presents a hybrid indoor positioning method with RFID and Magnetic Field.The new method divides the mapping area into several classes based on a clustering method.A matching into class based on the wireless signal was done first and then accurate location was determined with magnetic field.Firstly,the thesis introduces the indoor location technology based on wireless and magnetic filed,analyses the influencing factors,highlights the fingerprint-based technology for indoor location.Then, it analyses the distribution of the wireless signal and the magnetic field, processes data and establish map.Finally,it describes the presented method.In order to further improve the performance of the mapping area divided,during the off-line stage, an improved K-means clustering method is proposed where clustering center is weighted with a correlation coefficient.During the on-line stage,the author employs the measured value to improve the location of particles and thus resolving the problem of losing effective particles.The result shows that the proposed method can reduce the computational complexity and improve the positioning accuracy.