Research On RFID Based 3D Positioning Algorithm

In recent years, with the rapid development of the mobile communications and wireless technology, and the concepts of "context-aware services" and "ubiquitous computing" were proposed, the acquision and processing of the information of the objects in the environment was needed in more and more applications, perceiving a variety of changes in the environment and accessing a variety of background services were also needed in these applications. Among them, acquision of the location information of the service object determines the context-aware services can be implemented accurately and efficiently or not. Therefore, people pay more and more attention in the wireless location technology. RFID technology has the advantages of large capacity, small size, non-contact, low-cost, high accuracy, long life, high sensitivity, the ability to adapt to the environment and so on.So, the RFID technology became the target location in the technology of choice for indoor environment, and an increasing number of applications require height or depth positioned to target objects, so this paper studies the three-dimensional positioning algorithm based on the RFID technology.We propose two 3D positioning algorithm after studied the classic positioning algorithm based on RFID. They are 3D positioning algorithm based on improved BVIRE and the MR-VLM 3D positioning algorithm. The 3D positioning algorithm based on improved BVIRE, extend the BVIRE algorithm to the three-dimensional space, propose a new model of 3D positioning and improve the two drawbacks of the BVIRE algorithm in two respects. Firstly, we use ternary-order nonlinear interpolation algorithm to calculate the RSSI value of the virtual reference tags, instead of a linear interpolation algorithm. Secondly, we propose the concept of the 3D density map, it is used in the improvement of the refinement method of the potential label area of the target tags. The MR-VLM 3D positioning algorithm use added mobile RFID readers which are located in the plane where the height is H/2(H is the height of the positioning space), the inclusiveness and exclusiveness constraint is enhance by the movement of the mobile RFID readers. So, it can not only reduce the range of the potential location area of the target tags, but also effectively prevent the RFID reader blind. In this paper, we use MATLAB to simulate these two 3D positioning algorithm based on RFID. The experiments demonstrate that the positioning accuracy of the 3D positioning algorithm based on improved BVIRE is 12.8%～41% higher than the BVIRE algorithm, the positioning accuracy of the MR-VLM 3D positioning algorithm is 22.97%～42.74% higher than the VLM 3D positioning algorithm.