On-body sensor system with dynamic re-calibration for positioning accuracy
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Solution Overview
Problem
On-body sensor systems face challenges in maintaining accurate positioning of sensor elements due to changes in skin transmission characteristics over time, leading to inaccurate monitoring of physiological parameters when patients replace or reposition the sensors at home.
Innovation Solution
An on-body sensor system with at least two skin interface units and a controller that performs re-calibration procedures to determine and correct body-transmission parameters based on known initial positions, ensuring accurate positioning and monitoring of physiological parameters.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If initial calibration is performed to determine body-transmission parameters, then positioning accuracy is improved, but the system becomes unreliable over time due to changes in skin transmission characteristics
Solution Approach 1:
The system transitions from static initial calibration parameters to dynamic real-time parameter determination. The controller continuously determines body-transmission parameters based on current signal characteristics rather than relying on fixed initial values, adapting to changing skin properties over time and throughout the day.
Solution Approach 2:
The system performs preliminary calibration to establish initial body-transmission parameters, then uses these as a baseline for subsequent real-time adjustments. This preliminary action provides a reference framework that is continuously refined through ongoing measurements and parameter updates.
2Measurement precision
If re-calibration procedures are performed frequently to maintain accuracy, then positioning precision is improved, but device complexity and user burden increase
Solution Approach 1:
The system performs automatic self-calibration without requiring user intervention. The controller autonomously determines body-transmission parameters by analyzing signal characteristics between skin interface units, eliminating the need for manual re-calibration procedures while maintaining high positioning precision.
Solution Approach 2:
The system continuously monitors signal characteristics between skin interface units and uses this feedback to automatically adjust and determine accurate body-transmission parameters in real-time. This closed-loop feedback mechanism maintains precision without requiring explicit user actions or complex manual procedures.
3Measurement precision
If multiple skin interface units are used for signal transmission and sensing, then positioning accuracy is improved, but the system becomes more complex and harder to operate
Solution Approach 1:
The system combines multiple skin interface units into a single integrated monitoring system with centralized control. The controller manages signal transmission and sensing across all units automatically, presenting a unified simple interface to the user while leveraging the enhanced positioning accuracy from multiple sensing points.
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 ensures reliable and accurate monitoring of physiological parameters by dynamically adapting to changes in skin transmission characteristics, allowing for precise repositioning of sensor elements and maintaining monitoring accuracy even after initial calibration.
Implementation Method 1
measured by generating and capacitively coupling an electrical signal having a known frequency and amplitude at one point on the human body
Implementation Method 2
The coupled signal is then sensed and measured at a different, remote point on the body by a sensor
Implementation Method 3
Due to the phase delay inherent in propagating the high frequency AC signal through the body, a phase difference can be observed between pairs of electrodes. The SkinTrack system measures these phase differences to compute a 2D coordinate location
Data Source
AI summary
An on-body sensor system (30) comprises at least two skin interface units (32, 34) for coupling signals into and out of the body, with one of the units being for placement at a known location. One unit applies electrical signals to the body and the other senses them at a remote location. By analyzing the sensed signals using a set of pre-determined body-transmission parameters, a position of one of the skin interface units can be determined. This allows accurate placement of one or the units, for instance to allow more accurate monitoring of physiological parameters using the unit. The body transmission parameters can change over time, whereas once the interface units are put in position, their position is stable. Hence the system also includes functionality to re-calibrate the transmission parameters using at least one known stable set of initial positions of the interface units. The re-calibration comprises a process of re-calculating the parameters based on the known positions. These can then be stored and used for future determinations of the position of the one of the skin interface units having a moveable location, for instance in the case that it is re-positioned or replaced.