| With the increasing types of positioning technology，People’s requirement on thepositioning accuracy is rising. At present，GPS positioning system has gone deep intopeople’s lives, but GPS is not applicable for indoor environment, because of the buildingblock and positioning accuracy. RFID tag has a rich data capacity, durability, repeatableread/write, Non line of sight and other advantages. Therefore, the localization base onRFID has been studied extensively.At present, some indoor positioning algorithms still have some problems, such as thebad positioning accuracy, the high cost, the complexity of the algorithm, bad real-time, andeasily affected by the surrounding environment. This paper is intended to improve thepositioning accuracy and research on both two-dimensional and three-dimensionallocalization algorithm. The specific contents are as follows:1) Aiming at the low positioning accuracy and large fluctuation of the current indoorpositioning algorithm in wireless sensor networks, a positioning algorithm of dynamicallyincreasing nearest virtual reference tags is put forward and implemented. Firstly, thismethod selects some reference tags that are close to the unknown tag through the Euclideandistance. Secondly, it divides the area according to the Euclidean distance of the referencetags which are selected and finds the areas that the unknown tag may be located in. Then itcalculates an intersection of these areas. Finally, in order to make the virtual signal strengthcloser to the actual value, this method adds the virtual reference tags to approach theunknown tag dynamically in the last minimum area.2) Based on2-D positioning algorithm, the3-D positioning algorithm introduce ‘Z’axis, and arrange the reference tags to the3-D space. First positioning the unknown tagwithin a hexahedron, that is made of eight reference tags. Then this method divided thehexahedron into eight parts. Secondly, the virtual reference tags were inserted into thehexahedron dynamically. After that re-select the nearest reference tags which are closest tothe unknown tag.Finally, weighted the3D coordinate values to locate the unknown tags.3) The Lagrange interpolation method is used to calculate the virtual tag’s signalstrength value and accomplished the2-D and3-D indoor positioning algorithm. Then compare with the improved algorithm. Simulate the real application environment thendirectly display positioning result. The result shows that the error of the improvedpositioning method improving the indoor positioning accuracy greatly. |
