Research On Warehouse Rfid Localization Method Based On Dynamic Division Scheme

With the proposal of the concept of service oriented, target objects' position information is more and more important for system application. Especially in the manufacturing field and warehousing logistics environment, goods' real time position information plays a very important role in monitoring and management of the goods. The global positioning system(GPS) is the most widely used positioning system in the world. However, when comes to indoor circumstances, GPS is unsuitable because of its bad performance in obstruct environment, i.e., the inability of satellite signals to penetrate buildings. As the last kilometer of the outdoor positioning, the development of indoor localization technology is relatively slow. The existing indoor positioning solution mainly includes infrared based location, WLAN(wireless local area network) based location, ultrasound based location, Bluetooth based location, and RFID(Radio Frequency Identification) based location. RFID technology received considerable attention in indoor localization domain for its advantages of non-line of sight(NLOS), multi-target, fast tracking, short time delay, non-touch and low cost.In this paper, we deeply analyzed the classical RFID localization methods and their deprived methods combined with the actual research of a large warehouse. On that basis, a dynamic division based RFID localization approach and reference tags' evaluation mechanism were brought out and were applied to practical application. The algorithm was simulated at last. The performance was analyzed from various angels. The work of this thesis is carried out as follows:(1) Researched the core technology of RFID indoor localization and the relevant theory, studied the theory and methodology of LANDMARC solution,VIRE solution and their deprived solutions. Generalized the deprived solutions from the angle of sensing area's division scheme, reference tags' reliability evaluation and virtual tags' interpolation.(2) The composition architecture of the RFID system is analyzed, corresponding localization solutions are designed for different type of shelves based on the actual demand of warehouse environment. The affecting factors of RFID position precision are determined combined with propagation characteristics of radio signal.(3) A new reference tag evaluation scheme is brought out, reference tags are divided into two kinds, master reference tags and slave reference tags, master-slave reference tags are used to separate the sensing area. The shortcomings of artificial division are analyzed, and on that basis, a dynamic division scheme is present to make compensation.(4) Simulation environment is built, the dynamic division based solution is evaluated in system efficiency, asymptotic time complexity and error distribution. Comparisons were made with the existing algorithms to analyze its performance.Experimental results and practical application showed that the novel reference tag evaluation scheme could effectively avoid misjudgment, and the stepped positioning method could reduce redundant computation and improve system efficiency. The dynamic division scheme could eliminate the error that artificial segmentation brought in.