RFID Tag Read Classification for False-Positive Location Filtering

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Solution Overview

Problem

Existing RFID systems face challenges in accurately tracking items due to signal attenuation and interference from reflective materials, leading to false positives and difficulty in determining the precise location of RFID tags, especially in environments with multiple antennas and high-power transmission.

Innovation Solution

The system generates linearized power data by partitioning read data into frames, calculating summated power values, and applying predicates to evaluate RFID tag behavior, thereby improving the accuracy of RFID tag identification and location determination.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If high-power RF signals are used to improve tag read reliability in reflective environments, then tag detection reliability improves, but false positives increase and location precision deteriorates

Engineering Contradiction:
Improvetag detection reliabilityVSAvoidlocation precision
Core Design Contradiction:
ReliabilityVSMeasurement precision

Solution Approach 1:

The patent segments the continuous read data into discrete frames and further divides each frame into individual read events. This segmentation allows the system to analyze temporal patterns of reads within each frame, distinguishing between genuine tag presence (consistent reads across multiple events) and false positives (sporadic or inconsistent reads), thereby maintaining high detection reliability while improving location precision

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent implements feedback mechanisms by evaluating read data against predetermined criteria and using the results to adjust system behavior. The system continuously monitors read patterns, compares them against expected behavior, and uses this feedback to filter false positives while maintaining sensitivity to genuine tag presence, resolving the contradiction between reliability and precision

Inventive Principle:
Principle #23Feedback

2Measurement precision

If RFID tags are interrogated numerous times to track item locations, then tracking accuracy improves, but false positives increase in reflective environments

Engineering Contradiction:
Improvetracking accuracyVSAvoidfalse positive rate
Core Design Contradiction:
Measurement precisionVSReliability

Solution Approach 1:

The patent applies dynamic evaluation criteria that adapt to environmental conditions. Rather than using fixed thresholds for determining tag presence, the system dynamically adjusts evaluation criteria based on observed read patterns, signal strength variations, and environmental factors. This allows the system to maintain high tracking accuracy while reducing false positives by adapting to changing conditions in reflective environments

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent performs preliminary evaluation of read data frames against predetermined criteria before finalizing location determinations. By pre-screening read data and identifying patterns indicative of false positives before they affect tracking decisions, the system can maintain accurate tracking while filtering out spurious readings that would otherwise increase false positive rates

Inventive Principle:
Principle #10Preliminary action

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 confidence in identifying and tracking RFID tags by reducing false positives and improving location precision, even in environments with reflective materials and multiple antennas.

Implementation Method 1

an RFID reader or interrogator retrieves information stored on a tag through a return radio frequency ('RF') signal picked up by the reader's antenna

Methodology Applied
Scientific EffectElectromagnetic radiation: Electromagnetic Induction

Implementation Method 2

generates linearized power data representing read data received from one or more RFID tags... linearizing the power values provided in the read data

Methodology Applied
Scientific EffectSignal strength measurement:

Data Source

PatentEP4495825B1Classifying RFID tag reads to increase confidence of tag inventory
Publication Date: 2026.04.22 UNITED PARCEL SERVICE OF AMERICAN INC
  • EP4495825B1 patent drawingFigure 1
  • EP4495825B1 patent drawingFigure 2
  • EP4495825B1 patent drawingFigure 3A~3B

AI summary

In general, various embodiments of the present disclosure provide methods, systems, computer-readable media, and/or the like for providing improved evaluation of read data collected from radio frequency identification ("RFID") tags. In various embodiments, a method is provided that comprises: receiving a data frame that comprises read data collected from an RFID tag over an interval of time, the RFID tag responding to receiving a RF signal sent from an antenna in communication with a reader, and the read data comprising RSSI values; generating a linearized power value for each RSSI value to form a set of linearized power values; summating the set of linearized power values to generate a summated power value for the data frame; evaluating the summated power value to determine that the summated power value meets a target predicate; and in response, causing an action to be performed with respect to the RFID tag.