FMCW Radar Range-Bin Selection for Accurate Vital Signals
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Solution Overview
Problem
Existing FMCW radar systems face challenges in accurately detecting vital signals due to limitations in distance resolution, clutter interference, and inaccurate range bin selection, particularly when targeting multiple targets with high sensitivity and high signal-to-noise ratio.
Innovation Solution
A method and system for enhancing vital signal detection by converting radar signals into range bins, tracking peak bins, extracting phase and magnitude signals, and selecting optimal range bins using a correlation coefficient between phase and magnitude signals, with adaptive phase unwrapping to remove noise and clutter, and filtering vital signal bands.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If 24 GHz FMCW radar is used, then the system can operate in ISM band with simpler regulations, but the distance resolution deteriorates to 60 cm due to narrow bandwidth
Solution Approach 1:
The patent segments the detection process into multiple range bins, allowing the system to analyze different distance intervals separately. This enables accurate vital signal detection even when the overall distance resolution is limited, by focusing computational resources on specific regions of interest
Solution Approach 2:
The patent changes the analysis parameter from raw distance measurement to phase signal analysis. By extracting phase information from radar returns and analyzing correlations across range bins, the system achieves accurate target detection without requiring high distance resolution
2Device complexity
If maximum value target detection method is used, then the processing is simple, but the accuracy of vital signal detection deteriorates due to inaccurate range bin selection
Solution Approach 1:
The patent implements feedback by calculating correlation coefficients between phase and magnitude signals across range bins. This feedback mechanism identifies the optimal range bin containing the target, allowing the system to iteratively refine its detection accuracy while maintaining computational efficiency
Solution Approach 2:
The patent combines multiple signal types (phase signals and magnitude signals) to create a composite detection approach. By analyzing the correlation between these different signal components, the system achieves more accurate target detection than using either signal type alone
3Measurement precision
If phase profile information is used for target detection, then the detection capability is enhanced, but the system complexity increases due to additional processing requirements
Solution Approach 1:
The patent extracts only the essential phase information from the radar signals, separating it from other signal components. By focusing computational efforts on extracting and analyzing phase profiles rather than processing complete raw signals, the system enhances detection capability while controlling complexity
4Measurement precision
If 60 GHz mmWave radar is used, then the distance resolution improves to 2.5 cm due to wide bandwidth, but the device size and weight increase
Solution Approach 1:
The patent creates a virtual high-resolution range profile by correlating phase and magnitude signals across multiple range bins. This computational copying technique achieves accurate target localization without requiring the physical hardware of high-frequency mmWave radar, thereby reducing system weight and complexity
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
Improves the accuracy and performance of vital signal estimation by accurately selecting range bins with strong vital signals, reducing noise interference, and maintaining continuous tracking of targets, achieving higher signal-to-noise ratios and shorter frame times.
Implementation Method 1
converting radar signals which are pre-processed after being reflected and received from a human body
Implementation Method 2
A distance measurement method of the UWB radar measures the time it takes for a very short specific radio frequency (RF) signal (impulse signal) to reflect and return after being transmitted
Implementation Method 3
FMCW radar that enables high-speed waveform frequency modulation of high-frequency radar has been developed
Implementation Method 4
extracting phase signals of the plurality of range bins including the peak range bin
Data Source
AI summary
There is provided an FMCW radar target detection method for vital signal detection. A method for detecting vital signals by using radar selects a range bin where there are accurate vital signals by using a correlation between a phase change profile of an IF signal caused by a minute motion, and a target signal intensity change profile, so that accuracy of estimation of vital signals can be enhanced through exact tracking of a person (target). In addition, clutter may be exactly removed by utilizing a phase unwrapping technique which is adaptive to an upper body motion change compared to a 180-degree fixed phase unwrapping technique.