An RF tag indoor positioning system and method based on OFDM
A positioning method and label technology, applied in the field of positioning, can solve the problems that cannot meet the requirements of high-precision positioning, the judgment of the distance and angle of the RF reader is difficult, and it is easy to cause errors, etc.
Active Publication Date: 2019-06-11
重庆谷庚科技有限责任公司
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Problems solved by technology
[0004] The RF signal has to be reflected from different obstacles before reaching the LMU. Due to the many obstacles in the indoor environment and the limited space, it is difficult for the RF reader to judge the distance and angle, which is easy to cause mistakes, resulting in large positioning errors.
Can not meet the requirements of indoor high-precision positioning
Method used
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[0024] The present invention will be further described below in conjunction with accompanying drawing.
[0025] Such as figure 1 As shown, it is a block diagram of the RF tag positioning system based on OFDM, and the RF reader transmits a high-power pure carrier signal to the RF tag. Including: RF reader, RF tag, position measurement unit LMU, RF reader sends high-power pure carrier to provide energy to the RF tag through the RF transceiver, modulates the authentication and identification information of the target tag, and decodes the authentication and identification information of the tag , to complete the energy supply and communication with the tag. The RF tag obtains the induced current from the RF reader through the antenna to supply energy for the tag, and the induced current carrying the information passes through the RF front-end circuit, and the detected digital signal is sent to the logic control circuit for information processing, and the backscattered signal pass...
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The invention discloses an RF label indoor positioning method and system based on OFDM, and relates to an indoor positioning technology. An RF reader-writer transmits a high-power pure carrier signalfp, and after the RF tag receives the high-power signal and is activated by power supply, the stored tag identity information and the OFDM sequence information are modulated to the carrier signal, andthe modulated signal is backscattered to the position measurement unit LMU. The LMU extracts the RF label information from the received signal; calculates the channel state response information whichtakes fp frequency as a center and contains a plurality of subcarriers, uses the fractional Fourier transform to obtain a function related to signal delay by the channel state response, estimates thedistance from the RF tag to the LMU, and solves the accurate distance from the RF tag to the LMU by using a reflection path suppression algorithm. The LMU establishes an array flow pattern about thephase difference and angle of subcarriers according to the channel state response under the multi-carrier and multi-antenna condition, and solves the AOA of the signal; and the LMU obtains the distance information and angle information of the RF tag, and combines the distance information and the angle information to realize single-station positioning of the RF tag.
Description
technical field [0001] The invention belongs to positioning technology and relates to indoor positioning of RF tags. Background technique [0002] Radio Frequency Identification Technology RFID (Radio Frequency Identification) is a non-contact automatic identification technology. The RFID system consists of three parts: scanning antenna, RF (radio frequency) reader, and RF (radio frequency) tag. RF tags consist of a microchip, memory and antenna. Radio Frequency Identification uses electromagnetic fields to automatically identify RF tags attached to objects, which contain electronically stored information. The passive tag collects energy from the radio waves of the attached RFID reader, and the LMU estimates the distance between the LMU and the tag by obtaining the CSI (Channel State Information) signal. After obtaining the CSI signal under multi-antenna and multi-carrier , can realize the wireless positioning of the tag. Moreover, the RFID tag does not need to be in the ...
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IPC IPC(8): H04W4/80H04W4/33H04W64/00H04B17/391H04L27/26
Inventor 金悦
Owner 重庆谷庚科技有限责任公司