Research On Localization Technique Of RFID In Indoor Space

With the development of Io T technology, the requirement for obtainment of information from the objective physical world has gradually increased. The continuous application of Context Awareness and other related technologies propose a higher request of RFID technology. RFID technology, as a core component of Internet of Things technology, is widely used in various fields such as basic services, national defense and so on. In the process of application, RFID-based localization issues received particular attention. When we monitor a certain event, a certain important figure or an important item, the primary problem we concerned about is its position.Most of the existing location technology confined to the outdoor environment, however, indoor space is limited by factors such as multipath, changing interferences and non-line-of-sight which makes the existing location technology not applicable for the location demands. Moreover, the positioning program in the office, airport lounge, library, lecture hall and other related scene is relatively few. It is particularly important to propose localization algorithms based on these indoor space environments which have good adaptability and can achieve a certain accuracy. The main research are as follows:(1) A gradient and constant-game based indoor RFID localization algorithm is proposed in this thesis. It is enhanced on the basis of the arrival time programs for the specific space scene, in which symbols and gradient are brought. The positioning accuracy of the target node is improved by the game results of gradients in different directions. Algorithm can adapt interior space scene and is able to achieve localization in the polygon interior space.(2) Strategy of perception ruleset based RFID indoor symbolic localization algorithm in constrained space is proposed in this thesis. It can achieve precise positioning on indoor space which have square constraints. This new method contains semantic information of space, and defines positioning strategy to realize indoor localization. The positioning method focuses on the scene with square constraints, and locate the position of the target label through the establishment of strategies. This positioning method is a new mean distinguished from coordinate localization, as it does not depend on the indoor coordinate system, and only need match indoor related symbols to obtain the target node position.(3) Doppler model based RFID indoor localization algorithm in limited indoor space is proposed, which focuses on indoor corridors, coal mine tunnels and other linear constrained space. This method makes use of Doppler model, which arranges multiple readers in indoor space. It can get the localization of target by adjustment of readers' range and other means. This method can correct readers' recognition range adaptively in linear constrained space, so as to achieve efficient indoor localization. The method abstracts the special indoor space, limits the interference between the signal and ensures the localization accuracy. Information obtained in this way can also get historical track of a moving object.