RFID Phase Discontinuity Correction via Slope Prediction
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Solution Overview
Problem
RFID tags in motion experience phase discontinuities due to relative velocity, leading to inaccurate distance calculations and ambiguity in location determination, which existing RFID readers struggle to correct effectively.
Innovation Solution
A method and system that calculate a phase-time slope for the RFID signal, estimate a predicted phase reading, and adjust the calculated distance based on detected phase discontinuities, allowing for accurate tracking of moving RFID tags by correcting for phase ambiguities.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the RFID tag moves at high velocity relative to the RFID reader, then the productivity of the system increases, but the radio signal experiences phase discontinuity and becomes corrupted
Solution Approach 1:
The system performs preliminary actions by calculating the phase-time slope from previous phase readings before the discontinuity occurs, and uses this slope to predict the expected phase at the current time. This predictive approach allows the system to prepare for and correct phase discontinuities before they completely corrupt the signal, maintaining reliable distance measurement even at high conveyor speeds
Solution Approach 2:
The system implements feedback by continuously monitoring the difference between predicted phase readings (based on phase-time slope) and actual phase readings. When a discrepancy indicating phase discontinuity is detected, the system adjusts the distance calculation accordingly. This closed-loop feedback mechanism ensures signal reliability maintains即使在high velocity conditions
2Speed
If the velocity of the RFID tag relative to the RFID reader increases, then the productivity improves, but the phase discontinuity occurs leading to inaccurate distance calculation
Solution Approach 1:
The system calculates the phase-time slope from historical phase data before the discontinuity fully impacts measurement accuracy. By establishing this predictive model in advance, the system can compensate for the effects of high relative velocity and maintain accurate distance calculations even when the RFID tag moves quickly through the scanning zone
Solution Approach 2:
The phase-time slope acts as an intermediary element that bridges the gap between predicted and actual phase readings. When phase discontinuity occurs due to high velocity, the slope provides a reference value that mediates the correction process, allowing the system to recover accurate distance measurements despite the signal corruption caused by rapid motion
3Device complexity
If conventional RFID reading methods are used without phase correction, then the device complexity remains low, but the location determination becomes ambiguous
Solution Approach 1:
The system performs preliminary phase analysis by calculating the phase-time slope from previous readings before making distance determinations. This upfront preparation allows the system to detect and correct phase discontinuities proactively, preventing location ambiguity without requiring complex additional hardware or fundamentally redesigning the RFID system architecture
Solution Approach 2:
The patent replaces complex mechanical or hardware-based phase correction mechanisms with a computational approach. By using software algorithms to calculate phase-time slopes and detect discontinuities, the system achieves accurate location determination without adding physical complexity to the RFID reader or tag hardware, thus maintaining system simplicity while improving location accuracy
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
This approach enables precise distance determination of moving RFID tags, enhancing the accuracy and functionality of RFID readers, particularly in applications like package sorting facilities where increased conveyor speeds require accurate locational data.
Implementation Method 1
When energized, an RFID tag produces a radio signal that can be used to identify the RFID tag (and thereby an associated object) at a distance and without physical contact via an RFID reader
Implementation Method 2
depending on the velocity of the RFID tag relative to the RFID reader, the radio signal may experience a discontinuity or otherwise become corrupted
Data Source
AI summary
Radio frequency identification discontinuity correction is provided by calculating a phase-time slope for a Radio Frequency Identifier (RFID) signal received from an RFID tag; estimating, based on the phase-time slope, a predicted phase reading for the RFID signal at a given time; and in response to detecting a phase discontinuity based on a difference between the predicted phase reading and an actual phase reading for the given time, adjusting a calculated distance to the RFID tag. The calculated distance may indicate that the RFID tag is inside of or outside of a designated zone, and that a motion of the RFID tag indicates travel towards or away from the designated zone, which may be used to add or remove an item associated with the RFID tag to an ongoing item list.