RFID Tag Locator Using Phase Geometry for Precise Direction Finding
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Solution Overview
Problem
Existing wireless tag communication systems struggle with inaccurate estimation of the direction and position of RFID tags due to the inability to accurately determine the distance between the communication device and the tag, leading to reduced accuracy in direction estimation.
Innovation Solution
A wireless tag communication apparatus that includes a communication device, sensor, display, and processor to determine the position of the RFID tag by calculating the midpoint between positions with the same phase of radio waves received, using central angles and sector formation to improve positioning accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the wireless tag communication apparatus uses conventional direction estimation methods without phase-based calculations, then the device complexity is lower, but the measurement precision of tag position and direction is reduced
Solution Approach 1:
The patent changes the parameter used for position estimation from signal strength (RSSI) to phase information of received radio waves. By utilizing phase differences of radio waves at multiple positions, the system achieves more accurate direction and position estimation without requiring complex additional hardware, thus resolving the contradiction between measurement precision and device complexity.
2Measurement precision
If the wireless tag communication apparatus moves along an arc path to collect phase data, then the measurement precision of tag position is improved, but the time required for position determination increases
Solution Approach 1:
The patent performs preliminary actions by pre-establishing the arc path and pre-calculating the relationship between phase differences and position. During actual operation, the system only needs to measure phase differences at positions along the pre-defined arc, which significantly reduces the time required for position determination while maintaining high precision.
3Ease of operation
If the display shows the determined tag position, then the ease of operation is improved, but the device complexity increases due to additional display control requirements
Solution Approach 1:
The patent implements self-service by automatically calculating and displaying the tag position without requiring manual intervention or complex user input. The system autonomously processes phase measurement data, determines position through geometric calculations, and presents the results on the display, thereby improving ease of operation with minimal increase in device complexity.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
Enhances the accuracy of estimating the direction and position of RFID tags by utilizing phase-based calculations and geometric methods, providing precise guidance for tag detection.
Implementation Method 1
a processor configured to determine a position of the wireless tag based on phases of the radio waves
Data Source
AI summary
A wireless tag communication apparatus includes a communication device that faces a first direction and configured to communicate with a wireless tag and receive radio waves, a sensor configured to detect positions of the apparatus, a display that is connected to the communication device and faces a second direction, a grip connected to the device, and a processor configured to: determine, as a first position, a midpoint between two positions that are on an arc along which the apparatus is moved, phases of the radio waves received at the two positions being same, determine a second position that is on the arc, calculate a central angle of a sector formed by the first position, the second position, and the arc, determine the position of the wireless tag using the central angle, the first position, and the second position, and control the display to display the determined position.