RFID Head Tracking Orientation via Transponder Signal Response

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Solution Overview

Problem

Conventional head-tracking systems for simulating surround sound with headphones require significant hardware effort and are costly, as they need mechanical angle measurement devices or complex signal transmission and processing, which is not efficient for wireless headphones.

Innovation Solution

A tracking system using RFID technology with passive or active RFID transponders attached to headphones, where a single transceiver emits a signal and detects orientation-dependent responses from transponders with different orientations, allowing orientation tracking without separate synchronization channels or direct visual contact.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If mechanical angle measurement devices or complex signal transmission systems are used for head-tracking, then orientation tracking accuracy is improved, but device complexity and cost increase significantly

Engineering Contradiction:
Improveorientation tracking accuracyVSAvoidhardware requirements
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent replaces mechanical angle measurement devices with an electromagnetic field-based RFID system. A transceiver emits electromagnetic signals that interact with transponders attached to the headphones, and the orientation is determined by analyzing the electromagnetic responses rather than using mechanical sensors or complex signal transmission hardware.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent uses passive RFID transponders which are inexpensive, small, and require no power supply. These transponders can be attached to the headphones without adding significant weight or complexity, providing a cost-effective alternative to expensive mechanical tracking devices.

Inventive Principle:
Principle #27Cheap short-living objects (Disposable)

2Device complexity

If passive RFID transponders are used without separate power supply, then device complexity is reduced, but energy for signal response must be obtained from the transceiver signal

Engineering Contradiction:
Improvepower supply requirementsVSAvoidenergy extraction from signal
Core Design Contradiction:
Device complexityVSUse of energy by moving object

Solution Approach 1:

The passive RFID transponders harvest the energy they need from the electromagnetic signals emitted by the transceiver. The transponders do not require separate power supplies or batteries; instead, they extract energy from the incident electromagnetic field to power their response transmission, making the system simpler and wireless.

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The patent combines the signaling and power transmission functions into a single electromagnetic field from the transceiver. The same signal that carries orientation information also provides the energy needed for the passive transponders to respond, eliminating the need for separate power supply channels.

Inventive Principle:
Principle #5Merging (Combining)

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 reduces hardware requirements and costs, providing a robust and cost-efficient method for determining the orientation of headphones, enabling accurate simulation of a stable sound field during head movements.

Implementation Method 1

A transceiver (10) connected to a processing unit (430) is fixed elsewhere in space. The transceiver (10) emits a signal and detects orientation-dependent responses from the transponders (40a, 40b)

Methodology Applied
Scientific EffectElectromagnetic radiation: Electromagnetic Induction

Implementation Method 2

Tracking system using RFID (radio frequency identification) technology

Methodology Applied
Scientific EffectRFID (Radio Frequency Identification): Electromagnetic Induction

Data Source

PatentEP2031418B1Tracking system using RFID (radio frequency identification) technology
Publication Date: 2017.11.01 HARMAN BECKER AUTOMOTIVE SYST GMBH
  • EP2031418B1 patent drawingFigure 1~2
  • EP2031418B1 patent drawingFigure 3A~3B
  • EP2031418B1 patent drawingFigure 4~5

AI summary

The present invention relates to a head-tracking system and method for determining at least one orientation parameter of an object on the basis of radio frequency identification (RFID) technology. At least two transponders the antennas of which have different orientations with respect to each other are attached to the object, while a transceiver connected to a processing unit is fixed elsewhere in space. An orientation of the object is evaluated based on the orientation-dependent responses of the transponders to a signal emitted by the transceiver. A tracking system according to the present invention is particularly advantageous since the additional wireless hardware with which the object has to be equipped (RFID transponders) consists of only small and low cost items. No special cabling is necessary. A preferred field of application of the present invention is orientation tracking of wireless headphones for simulating surround sound, such as in a vehicle entertainment and information system.