FMCW Radar Phase Correction for Biosignal Detection
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Solution Overview
Problem
Conventional information processing apparatuses using Doppler radar struggle to accurately sense objects with high resolution and precision, especially in detecting minute vibrations and biosignals, such as heartbeat or breathing, due to limitations in distance, speed, and angle measurement, particularly when the relative speed between the system and the object is zero.
Innovation Solution
The system employs a Frequency Modulated Continuous Wave (FMCW) radar with multiple transmission and reception antennas, utilizing phase correction algorithms to enhance resolution and accuracy in distance, speed, and angle sensing, allowing for the detection of micro-vibrations and biosignals with a resolution 100 to 1000 times higher than traditional millimeter wave radar, even at zero relative speed.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional Doppler radar is used for object sensing, then the system structure is simple, but the measurement precision and resolution are insufficient for detecting minute vibrations and biosignals
Solution Approach 1:
The patent divides the sensing system into multiple transmission antennas and multiple reception antennas, creating separate functional segments that work together to achieve high-resolution sensing. Each antenna pair contributes to specific spatial frequency components, enabling detailed vibration detection through coordinated operation of segmented components.
Solution Approach 2:
The patent transitions from conventional single-dimensional Doppler sensing to multi-dimensional sensing by incorporating multiple antennas arranged in specific geometries. This spatial dimensionality enhancement allows the system to capture vibration patterns from multiple angles simultaneously, achieving 100-1000 times higher resolution than traditional millimeter-wave radar.
2Reliability
If the radar system operates at zero relative speed, then energy consumption is reduced and stability is improved, but the ability to detect objects and measure speed deteriorates
Solution Approach 1:
The patent detects minute vibrations of objects (such as breathing or heartbeat) by analyzing reflected wave patterns from multiple antenna pairs. When the object vibrates, the phase and frequency of reflected signals change, allowing the system to detect these mechanical vibrations even when the overall relative speed between radar and object is zero, thus maintaining both reliability and speed measurement capability.
3Measurement precision
If multiple transmission and reception antennas are used to improve resolution, then measurement precision increases, but device complexity and processing requirements increase
Solution Approach 1:
The patent designs the multiple antenna system to perform multiple functions simultaneously: distance measurement, speed measurement, angle determination, and vibration detection. The same set of transmission and reception antennas serves all these purposes through different signal processing techniques, avoiding the need for separate specialized sensors for each function and thereby managing complexity while maintaining high measurement precision.
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 FMCW radar system effectively senses objects by modulating frequency and analyzing time differences, achieving precise distance, speed, and angle measurements, including biosignal detection with improved resolution and accuracy, enabling contactless monitoring of objects and structures.
Implementation Method 1
an information processing apparatus for sensing an object by using a Doppler radar is known
Implementation Method 2
The system employs a Frequency Modulated Continuous Wave (FMCW) radar with multiple transmission and reception antennas, utilizing phase correction algorithms
Data Source
AI summary
An information processing apparatus which senses an object by using an FMCW radar, wherein the information processing apparatus comprises: a data processing unit acquiring an angle power spectrum by performing angle FFT on a received signal; an acquisition unit acquiring an angle peak bin indicating an angle with the object; an extraction unit extracting an output signal corresponding to the power spectrum signal; and a correction unit correcting a phase of the output signal in accordance with a bin number of the plurality of peak bins, wherein the data processing unit applies a window function higher in order than a rectangular window function when performing the angle FFT, and the correction unit corrects the phase of the output signal so that a phase difference to be added or subtracted is (N−1)/2×π×sin(θ(i)) [rad] in accordance with the bin number of the angle peak bin.