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Phase Correlation Single Channel Continuous Wave Doppler Radar Recognition of Multiple Sources
Khaldoon Ishmael1, Yao Zheng1, Olga Borić-Lubecke1
1Department of Electrical and Computer Engineering, University of Hawai'i at Manoa, Honolulu, HI 96822, USA.
Sensors (Basel, Switzerland)
|February 15, 2022
Summary
This study introduces a novel phase tuning method for continuous-wave Doppler radar (CWDR) to separate signals from multiple, nearly equidistant targets. The technique successfully distinguishes individual physiological signals, even for targets positioned closely together.
Area of Science:
- Radar Systems Engineering
- Biomedical Signal Processing
- Remote Sensing Technology
Background:
- Continuous-wave Doppler radar (CWDR) is capable of remotely sensing physiological signals like respiration and heart rate.
- Separating signals from multiple targets, especially equidistant ones within a single beam, presents a significant challenge for CWDR systems.
- Existing solutions often involve complex hardware or advanced signal processing, with limited success in specific scenarios.
Purpose of the Study:
- To develop and evaluate a novel phase tuning approach for enhanced multi-target detection and separation using CWDR.
- To overcome the limitations of current methods in separating signals from closely spaced targets.
- To demonstrate the feasibility of separating physiological signals from multiple individuals using a single-channel CWDR system.
Main Methods:
- Implementation of a phase correlation system using a voltage-controlled analog phase shifter with a 2.4 GHz single-channel CWDR.
- Manipulation of CWDR phase correlation to create distinct signal mixtures from multiple targets.
- Sequential suppression of individual signals in the frequency domain for separation.
Main Results:
- Successful separation of nearly equidistant targets within a single antenna beam.
- Demonstration of the system's capability to distinguish physiological signals from two individuals positioned closely together (shoulder to shoulder).
- Validation of the phase tuning approach through experiments with mechanical and human targets.
Conclusions:
- The proposed phase tuning method offers an effective alternative for multi-target detection and separation in CWDR.
- This technique can successfully resolve signals from closely spaced targets, a significant advancement for remote physiological monitoring.
- The system shows promise for applications requiring the simultaneous monitoring of physiological parameters from multiple individuals in close proximity.
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