Indoor positioning method based on UHF RFID technology
In indoor environments,due to factors such as shielding effects of buildings and multipath fading,there are many re-flected and scattered signal paths.These multipath interferences introduce additional phase differences,and when the distance be-tween adjacent labels or signal sources is very close,the phase difference may exceed one wavelength,leading to phase ambiguity and the inability to accurately obtain the phase difference between different carrier signal sources,increasing the difficulty of localization.To address this issue,an indoor positioning method based on ultra-high frequency radio frequency identification(UHF RFID)tech-nology is proposed.Analyze the structure and working principle of UHF RFID system.After receiving the tag reply signal in the UHF RFID tag reader,calculate the phase angle of the ultra-high frequency carrier signal;Extract the phase of indoor passive ultra-high frequency signals based on the distance between the reader and the tag,and obtain the phase difference of different carrier signal sources;By fitting and analyzing the phase difference data,the phase difference is transformed into Euclidean distance data to solve the phase ambiguity phenomenon caused by the phase difference exceeding the wavelength;Perform eigenvalue decomposition on dis-tance data,construct a scalar product matrix of eigenvalues,extract signal features of label replies,and distinguish them from other signal sources;By combining known unknown node information and using the phase difference multi-dimensional scaling positioning algorithm to further optimize the positioning results,passive ultra-high frequency positioning can be achieved.From the experimental results,it can be seen that the proposed method has a maximum error of 0.01 rad between the phase difference of the ultra-high fre-quency signal and the actual value,and a maximum positioning error of only 0.12m.The positioning error is relatively small,and it can still maintain high positioning accuracy in complex channel propagation environments,with good positioning effects.
万方数据
维普
