Multi-Sensor Vital Sign Tracking with Radar-IMU Signal Fusion
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Solution Overview
Problem
Contact-based vital sign monitoring technologies are cumbersome, impractical, and prone to errors due to interference from bodily movements and environmental factors, limiting their effectiveness in continuous and accurate cardiovascular and respiratory tracking.
Innovation Solution
A multi-sensor system combining millimeter-wave FMCW radar sensors with proximity and inertial measurement units (IMU) to adjust the radar's view angle towards the subject's chest and filter out noise, enhancing accuracy by consolidating data from multiple sensors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If contact-based sensors (wires or cables) are used for vital sign monitoring, then measurement capability is achieved, but ease of operation and comfort deteriorate due to obtrusiveness and difficulty of implementation
Solution Approach 1:
The patent replaces mechanical contact-based sensors (wires, cables, elastic bands) with electromagnetic radar sensing technology. The millimeter-wave radar system detects vital signs through electromagnetic wave reflection from the body, eliminating the need for physical contact while maintaining measurement capability. This substitution resolves the contradiction by providing accurate measurements without the obtrusiveness of contact-based methods.
2Ease of operation
If optical interferometry is used for contactless sensing, then ease of operation improves, but reliability deteriorates because optical signals are blocked by clothes or other materials
Solution Approach 1:
The patent changes the electromagnetic wave parameter from optical frequency to millimeter-wave frequency (30-300 GHz). Millimeter waves have longer wavelengths than optical signals, allowing them to penetrate or pass through clothing and other materials that block optical signals. This parameter change enables reliable contactless sensing through clothes, resolving the contradiction between ease of operation and reliability.
3Ease of operation
If ultrasonic waves are used for contactless motion detection, then ease of operation improves, but measurement precision deteriorates due to poor signal-to-noise ratio from low reflection
Solution Approach 1:
The patent substitutes ultrasonic mechanical wave sensing with electromagnetic radar sensing. The millimeter-wave radar system transmits electromagnetic waves that reflect off the body with much higher signal strength compared to ultrasonic reflections. This substitution maintains contactless operation while dramatically improving signal-to-noise ratio and measurement precision through the superior reflective properties of electromagnetic waves at millimeter frequencies.
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 provides precise, contactless monitoring of cardiovascular and respiratory data by minimizing interference from bodily and environmental motions, improving measurement reliability and accuracy.
Implementation Method 1
millimeter-wave radar sensors such as millimeter-wave frequency modulated continuous wave (FMCW) radar sensors
Implementation Method 2
analyzing the reflections of millimeter-wave radar signals off the human body
Implementation Method 3
one or more proximity sensors may be used to determine a position of the subject's chest
Implementation Method 4
one or more inertial measurement units (IMU) sensors may be used to obtain a cardiovascular or respiratory measurement
Data Source
Figure 1A~1C
Figure 2
Figure 3
AI summary
Cardiovascular or respiratory data of a subject is measured using a multi-sensor system. The multi-sensor system includes a mm-wave FMCW radar sensor, an IMU sensor, and one or more proximity sensors. The mm-wave FMCW radar sensor may be selected and its view angle adjusted based on positioning data regarding the subject obtained from the one or more proximity sensors. Each of the mm-wave FMCW radar sensor and the IMU sensor may acquire cardiovascular or respiratory measurements of the subject, and the measurements may be fused for improved accuracy and performance.