Phase-type distance measuring method for ultrahigh frequency RFID (Radio Frequency Identification) positioning

A distance measurement method and ultra-high frequency technology, applied in measuring devices, using re-radiation, radio wave measurement systems, etc., can solve problems such as low precision and difficult time synchronization, achieve high precision, consume less resources, and be simple to implement Effect

Inactive Publication Date: 2013-10-16
TIANJIN UNIV
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Problems solved by technology

[0033] Aiming at the problems of low accuracy and difficult time synchronization in the current UHF ...

Method used

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  • Phase-type distance measuring method for ultrahigh frequency RFID (Radio Frequency Identification) positioning
  • Phase-type distance measuring method for ultrahigh frequency RFID (Radio Frequency Identification) positioning
  • Phase-type distance measuring method for ultrahigh frequency RFID (Radio Frequency Identification) positioning

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Embodiment Construction

[0054] Such as Figure 4 As shown, the present invention includes three main steps: performing band-pass sampling on the transmitted signal and received signal modulated by a single-frequency subcarrier; performing phase extraction on the discretized transmitted sequence and received sequence, and calculating the The distance information between them; the hyperbolic least squares algorithm is used for positioning.

[0055] In a nutshell, the phase-type ranging method for UHF RFID positioning of the present invention includes the following steps:

[0056] 1) According to the ISO / IEC18000-6C protocol, select the UHF carrier f c =915MHz, then the carrier wavelength λ c =c / f c =32.8cm (speed of light c=3×10 8 m / s), that is, the maximum measurement distance allowed is only λ c / 2=16.4cm, far less than the measurement distance.

[0057] 2) Aiming at the problem in 1), a single-frequency subcarrier amplitude modulation method is adopted, that is, a lower frequency subcarrier is...

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Abstract

The invention belongs to the field of signal processing, relating to a phase-based indoor positioning algorithm, especially to a phase-type distance measuring method for ultrahigh frequency RFID positioning. The method comprises that a single-frequency subcarrier amplitude modulation manner is carried out on selected ultrahigh carrier frequency and subcarrier frequency; it is presumed that emission signals are propagated in a line-of-sight manner; phases are extracted via a discrete frequency spectrum correction technology; a formula for calculating a phase difference of subcarrier signals at transmitting and receiving ends is obtained; distances between readers and a label are calculated; and in the whole positioning system, distances to the same label are respectively measured via the multiple readers, and under the condition that the distances from the readers to the to-be-measured label are known, the label is positioned via a dual-curve least square positioning algorithm. According to the phase-type distance measuring method for ultrahigh frequency RFID positioning, precision in positioning a moving object in a complex environment can be improved.

Description

Technical field [0001] The invention belongs to the field of digital signal processing, and in particular relates to a method for extracting the phase of an ultra-high frequency RFID transceiving signal and then performing distance measurement and positioning. Background technique [0002] Radio Frequency Identification (RFID) is an automatic identification technology that has matured since the 1980s [1], which uses radio frequency to exchange data to achieve target identification. Due to the non-contact characteristics of the radio frequency card, no manual intervention is required in the identification process, which is conducive to the realization of system automation. In recent years, RFID technology has been widely used in the fields of logistics, anti-counterfeiting, office, tracking and positioning due to its advantages of low energy consumption and good adaptability. 13.5MHz) products, but increased the research and development of ultra-high frequency band (860~960M...

Claims

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Application Information

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IPC IPC(8): G01S13/84
Inventor 马永涛刘开华任盈之
Owner TIANJIN UNIV
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