On-body sensor positioning via signal angle of arrival

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Solution Overview

Problem

Existing on-body sensing systems face challenges in ensuring accurate and reliable placement of sensor patches and handheld devices, particularly in home-based monitoring where patients or caregivers may lack medical training or experience with poor eyesight, dexterity, or cognitive function.

Innovation Solution

An on-body sensor system comprising skin interface units with reference units of known position and a positionable unit, utilizing electrical signals to determine the angle of arrival at reference units, and accessing a reference dataset to derive the position of the positionable unit for accurate placement.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If patients or caregivers place sensor patches without medical training or with poor eyesight/dexterity/cognitive function, then ease of operation is improved, but measurement precision deteriorates

Engineering Contradiction:
Improveease of placementVSAvoidplacement accuracy
Core Design Contradiction:
Ease of operationVSMeasurement precision

Solution Approach 1:

The system provides real-time feedback to the user through visual indicators (LED lights or display elements) that show whether the sensor patch is correctly positioned. The feedback mechanism compares the actual position with the target position and guides the user to adjust placement, ensuring high measurement precision even for untrained users with poor eyesight or dexterity.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The patent introduces an intermediary positioning system consisting of guide markers, alignment indicators, or robotic assistance that mediates between the user's placement action and the final sensor position. This intermediary layer ensures accurate placement without requiring the user to have medical training or fine motor skills.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Measurement precision

If reference units with multiple electrode pairs are used to determine angle of arrival, then measurement precision is improved, but device complexity increases

Engineering Contradiction:
Improveposition determination accuracyVSAvoidsystem complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The system divides the reference units into multiple distributed electrode pairs across the body surface. Each electrode pair independently measures signal characteristics, and the results are combined to determine the angle of arrival. This segmentation allows high measurement precision through multiple measurements while keeping each individual electrode pair simple in structure.

Inventive Principle:
Principle #1Segmentation

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

The system enables accurate and reliable positioning of sensor units, enhancing the reliability of physiological parameter monitoring and imaging data, even in non-clinical settings, by providing guidance for correct placement.

Implementation Method 1

skin interface units for coupling electrical signals into and/or out of the body of a subject

Methodology Applied
Scientific EffectElectrical signal propagation through body tissue: Conduction (electrical)

Implementation Method 2

derive at each reference unit one or more signal characteristics associated with signals received at each pair of electrodes respectively of the unit

Methodology Applied
Scientific EffectElectrical signal detection and measurement: Electrical Impedance Tomography

Data Source

PatentEP3813644B1On-body sensor system and method
Publication Date: 2025.04.23 KONINKLIJKE PHILIPS NV
  • EP3813644B1 patent drawingFigure 1a
  • EP3813644B1 patent drawingFigure 1b
  • EP3813644B1 patent drawingFigure 2

AI summary

An on-body sensing system (30) comprises a plurality of skin interface elements for coupling electrical signals to and from the body. The system is adapted to derive an indication of a position of at least one positionable interface unit (32) based on transmission of signals between the positionable unit and a set of spatially separated reference units (34), the reference units being positioned at a set of known locations on the body. Transmitted signals are sensed at multiple pairs (52) of electrodes on each reference unit and signal characteristics derived for each pair, and based on this a direction of arrival of the signal determined. By collating all of the measured arrival angles, and by reference to a reference dataset containing information indicative of known signal arrival angles when signals are transmitted internally between the reference units themselves, an indication of position of the positionable unit is derived.