RFID Tag Identification via Signal Variance Analysis

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Solution Overview

Problem

Existing RFID systems struggle to identify and track specific RFID tags among multiple tags due to the inability to differentiate based on variance in received parameters, leading to difficulties in controlling machines with varying tools attached.

Innovation Solution

A system that includes identification devices, a reading device, and a receiving device to obtain data samples, determine variance values, and evaluate these values to identify specific RFID tags, allowing for precise control of machine parameters based on attached tools.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Quantity of substance

If multiple RFID tags are within range of the RFID receiver, then the system can detect multiple tags, but the ability to identify a particular tool becomes more difficult

Engineering Contradiction:

Improvenumber of detectable tagsVSAvoiddifficulty of identifying particular tag

Core Design Contradiction:

Quantity of substanceVSDifficulty of detecting and measuring

Solution Approach 1:

The patent applies parameter changes by analyzing variance in received signal parameters (amplitude, frequency, phase) over time to distinguish between stationary tags and moving tags. The system calculates variance values for multiple tags and identifies tags based on their motion characteristics, resolving the identification difficulty when multiple tags are present.

Inventive Principle:

Principle #35Parameter changes

2Measurement precision

If the system compares signals at different times to determine relative change in distance, then tracking capability is improved, but the system cannot identify tags based on variance in received parameters

Engineering Contradiction:

Improveprecision of distance measurementVSAvoidinability to identify tag by variance

Core Design Contradiction:

Measurement precisionVSLoss of information

Solution Approach 1:

The system implements feedback by continuously monitoring signal parameters from RFID tags and using the variance information to identify and track specific tags. The receiving device evaluates variance values and provides feedback about tag identity and motion state, enabling both precise tracking and tag identification simultaneously.

Inventive Principle:

Principle #23Feedback

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

Enables accurate identification and tracking of RFID tags, enabling machines to adjust control parameters accordingly, improving operational efficiency and precision in tasks requiring different tool attachments.

Implementation Method 1

RFID tags for emitting short bursts of RF energy at periodic intervals

Methodology Applied

Scientific EffectRF energy transmission: Electromagnetic Induction

Implementation Method 2

RFID detectors for receiving signals from the particular RFID tag and control means for comparing the signals received

Methodology Applied

Scientific EffectRF signal detection: Electromagnetic Induction

Data Source

PatentUS7579952B2System and method to identify and track RFID tags

Publication Date: 2009.08.25 CATERPILLAR INC

AI summary

A system and method are disclosed that provide device recognition. The system has one or more identification devices and a reading device configured to obtain data from the one or more identification devices. The system also has a receiving device in communication with the reading device. The receiving device is configured to determine a variance value for each of the one or more identification devices based on data received from the reading device and evaluate the determined variance values to identify at least one of the one or more identification devices.