To address the issue of large positioning errors in complex environments within non-contact RFID-based posi-tioning systems,RFreeTrack system was proposed.Commercial RFID equipment was used to calculate the reflected sig-nals from targets,achieving high-precision non-contact positioning in complex environment.Firstly,a search method based on time-series similarity was proposed to employ for calibrating static signals,thus significantly enhanced the ro-bustness of target reflection signal extraction.Secondly,a non-contact positioning method based on differential phase holography was introduced to eliminate the influence of the reader antenna's position,thus the accuracy of position-ing was improved and the complexity of system was deployment reduced as well.Finally,a high-precision non-contact positioning system prototype was realized.Experimental results indicate that in complex environments,the phase of the target reflection signals extracted using the calibrated static signals has a 68.8%lower error com-pared to existing methods.Based on the previously calibrated static reflection signals,the average positioning error using differential phase holography in complex environments is 0.040 8 m,and has a 50.6%improvement on loca-tion over existing methods.
关键词
射频识别/室内定位/非接触式定位/静态信号校准/差分相位全息图
Key words
RFID/indoor localization/non-contact localization/static signal calibration/differential phase hologram
维普
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