RFID Load Classification via Doppler Shift Detection

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

Existing systems face challenges in accurately determining which objects with RFID tags belong to the load of a mobile device, such as a forklift, due to extraneous RFID reads and the need for complex tuning of RFID signals.

Innovation Solution

A mobile device equipped with an RFID reader and processing system that computes a speed estimate based on fixed RFID tags and classifies objects as belonging to the load or not based on movement indicators, eliminating the need for location estimation and signal modulation requirements.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If spatial identification technology is used to define a load space, then objects can be identified as belonging to the load, but careful tuning of power limits and other factors is required to achieve reliable identification

Engineering Contradiction:

Improveobject identification accuracyVSAvoidtuning complexity

Core Design Contradiction:

Measurement precisionVSDevice complexity

Solution Approach 1:

The patent replaces the mechanical/spatial approach of defining a load space with a Doppler-based detection method. Instead of using spatial boundaries and power tuning, the system uses Doppler shift measurements of RFID signals to detect relative motion between the mobile device and objects, automatically identifying load objects without requiring manual tuning of spatial parameters.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent changes the detection parameter from spatial position and signal power to Doppler shift frequency. By measuring the frequency shift caused by relative motion, the system can distinguish load objects from extraneous objects based on their motion characteristics, eliminating the need to tune spatial boundaries and power limits.

Inventive Principle:

Principle #35Parameter changes

2Reliability

If RFID signals are modulated with specific components, then signal detection can be improved, but the system requires specific signal modulation requirements

Engineering Contradiction:

Improvesignal detection reliabilityVSAvoidsignal modulation flexibility

Core Design Contradiction:

ReliabilityVSAdaptability or versatility

Solution Approach 1:

The patent replaces the signal modulation approach with a Doppler-based detection method that works with unmodulated or differently modulated RFID signals. By detecting the frequency shift caused by relative motion, the system can reliably identify objects without requiring specific modulation schemes like in-phase and quadrature components.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

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 solution effectively distinguishes between objects belonging to the load and those that do not, without requiring complex tuning or specific signal modulation, thereby enhancing the accuracy and reliability of load management.

Implementation Method 1

a radio frequency identifier reader configured to receive radiation emitted by the object-specific radio frequency identifiers

Methodology Applied

Scientific EffectRadio frequency radiation emission and detection: Electromagnetic Induction

Implementation Method 2

compute a speed estimate for the mobile device based on a distance between first and second ones of the fixed radio frequency identifiers and a time-difference between receptions of radiation from the first and second ones of the fixed radio frequency identifiers

Methodology Applied

Scientific EffectTime-difference of flight measurement: Time of Flight

Implementation Method 3

determine, based on radiation received from each of the object-specific radio frequency identifiers, a movement indicator indicative of movement of the mobile device with respect to the object provided with the object-specific radio frequency identifier under consideration

Methodology Applied

Scientific EffectDoppler shift detection: Doppler Effect

Data Source

PatentUS12304788B2Mobile device, a system, and a method for handling objects provided with radio frequency identifiers

Publication Date: 2025.05.20 TURCK VILANT SYST OY

AI summary

A mobile device for handling objects includes a radio frequency identifier reader for receiving radiation emitted by object-specific radio frequency identifiers attached to the objects and radiation emitted by fixed radio frequency identifiers. The mobile device includes a processing system that computes a speed estimate for the mobile device based on a distance between two fixed radio frequency identifiers and a time-difference between receptions of radiation from these fixed radio frequency identifiers. The processing system determines, based on radiation received from each object-specific radio frequency identifier, a movement indicator indicative of movement of the mobile device with respect to the corresponding object. When the speed estimate exceeds a threshold, the processing system classifies objects which are moving in accordance with the movement indicator to be objects non-belonging to a load of the mobile device. The mobile device can be for example a forklift.