摘要： 针对无线射频识别(RFID)的室内定位问题，提出一种基于读写器功率扫描的超高频射频识别标签定位方案。通过自由空间的电磁波路径损耗经验模型和Friis传输方程，建立读写器天线功率与当前功率感测范围直径的关系模型。分别使用多个天线进行定位比较，并分析影响系统定位精度的因素。实验结果表明，与使用2个天线相比，使用3个天线可将平均定位误差由57 cm减小到18 cm，且定位误差小于25 cm的概率大于90%。同时，减小读写器功率变化的步长也可显著降低定位误差。

关键词: 无线射频识别, 超高频射频识别, 标签, 定, 路径损耗, 功率-感测直径模型, 读取范围, 相交区域

Abstract: Aiming at Radio Frequency Identification(RFID) localization problem for indoor environments, an UHF RFID tag localization method based on power scanning of reader is proposed. A path loss model is proposed to study the power of reader as a function of read range. The function is analyzed based on an empirical model that often used in indoor environments and Friis transmission equation in theory, and demonstrated in experiments. Based on the function, a circle localization using multiple RFID antennas is proposed. Experiment demonstration using two antennas shows that the average accuracy value is 57 cm. The factors that affect the location accuracy are studied, and then an improved localization method is proposed. Statistical results indicate that the average accuracy is improved from 57 cm to 18 cm using three antennas, and the location accuracy in terms of 90% probability within 25 cm. Meanwhile, decreasing the step of the power adjustment can also improve the location accuracy.

Key words: Radio Frequency Identi?cation(RFID), UHF RFID, tag, localization, path loss, power-sensing diameter model, read range, intersection area

中图分类号: 

• TP393