Modified FMCW system for non-contact sensing of human respiration

Pramudita, Aloysius Adya; Suratman, Fiky Yosef; Arseno, Dharu

doi:10.1080/03091902.2020.1753835

Cited by 13 publications

(6 citation statements)

References 23 publications

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“…The use of extensive bandwidth increases the complexity in the realization of the radar and its implementation. To overcome these problems, the phase detection technique is then elaborated in detecting the small displacement phenomenon related to the respiratory activity [7], [14]. Several phase-detection methods have been proposed in vital signs radar, such as the use of the IQ demodulator circuit [1], [9], six-port network [36], and also using additional computation methods such as IQ demodulation [14] and FFT computation.…”

Section: S R (T)mentioning

confidence: 99%

“…To overcome these problems, the phase detection technique is then elaborated in detecting the small displacement phenomenon related to the respiratory activity [7], [14]. Several phase-detection methods have been proposed in vital signs radar, such as the use of the IQ demodulator circuit [1], [9], six-port network [36], and also using additional computation methods such as IQ demodulation [14] and FFT computation. In this research, the two steps of FFT computation are employed to detect the live victim's respiration vital signs under the rubbles.…”

Section: S R (T)mentioning

confidence: 99%

“…wall associated with respiratory activity. Detection of human breathing using a radar system applies the concept of a specific Doppler effect that arises when radar waves hit the chest wall or abdomen when breathing [1], [4], [14]. Detection of human breathing behind walls or barriers is also an interesting issue in developing respiration sensors based on radar systems.…”

mentioning

confidence: 99%

“…The breathing pattern is reflected in the movement of the chest or abdominal wall when inhaling and exhaling. The breathing pattern can be detected from the phase change of the beat signal [14]. The target distance from the radar can be estimated from the beat frequency value.…”

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confidence: 99%

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Radar System for Detecting Respiration Vital Sign of Live Victim Behind the Wall

et al. 2022

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The presence of an obstacle in detecting respiration vital signs using a radar system does not only exhibit attenuation and phase shift effects on the radar signal but also causes additional beat frequencies to appear beside those from the target. When a conventional FMCW radar system detects the peak of the received signal spectrum as a beat frequency, this will give an error of detection. The respiratory vital signs will then be undetectable. A method to overcome this obstacle problem is needed. Therefore the implementation of the FMCW radar system in detecting respiratory vital signs behind the wall can be realized. In this paper, a method to deal with the previously mentioned problem is proposed. The proposed method consists of a method for identifying the obstacle response. Then the results are used to eliminate the beat frequency that arises from the obstacle structure, and therefore the signal to clutter ratio (SCR) can be improved. Furthermore, the method is combined with the phase detection method, which is applied to extract the Doppler response related to the target respiratory vital signs. The weighting process by elaborating cross correlation is also employed for minimizing clutter from other objects reflection under debris. A laboratory experiment by developing an FMCW radar system with a 24 GHz frequency operation was performed in this research. The proposed detection method was elaborated in the post-processing of the radar system. The experiment result demonstrates that the proposed method is capable of eliminating the effect of the wall and successfully extracting the respiration vital sign pattern.

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Section: S R (T)mentioning

confidence: 99%

Section: S R (T)mentioning

confidence: 99%

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confidence: 99%

mentioning

confidence: 99%

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Radar System for Detecting Respiration Vital Sign of Live Victim Behind the Wall

et al. 2022

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“…The frequency modulation continuous wave (FMCW) radar has been widely used in human vital sign detection due to its straightforward structure, high sensitivity, and impressive range resolution [7,8]. The breathing pattern can be detected from the phase change of the beat signal [9]. The target distance from the radar can be converted from the frequency of the beat signal.…”

Section: Introductionmentioning

confidence: 99%

A Clutter Identification and Removal Method Based on Long Delay Lines and Cross-Correlation in Through-Wall Detection

Yuan,

Ji,

et al. 2024

Applied Sciences

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Life detection is important in earthquake rescue, but weak vital signal is susceptible to interference by clutters. Due to the undesirable characteristics of the hardware, there are two main types of clutter generated by the frequency modulation continuous wave (FMCW) radar when transmitting signals. One is generated by periodic nonlinearity during frequency modulation, and the other is generated by the phase-locked loop spuriousness (PLLS) in frequency division. They cause additional beat frequencies to appear beside those from the target, leading to false alarms. Since the suppression measures for them are different, it is necessary to distinguish the types of clutter and choose appropriate suppression methods. In this paper, the accurate theoretical modeling of the effects of the periodic nonlinearity and phase-locked loop spuriousness on the beat signal is performed to determine distinctions between them. The clutter occurring in the system used is identified as originating from phase-locked loop spuriousness through fiber-optic experiments. A method using long delay lines and cross-correlation is proposed to identify and remove it. In experiments, the false alarm rate is reduced from over 50 percent to nearly 0 percent, providing strong evidence for the effectiveness of the proposed method in through-wall detection.

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Small Displacement Detection System of Landslide Using FMCW Radar with Phase-Detection and Change Point Detection Method

Natalia

Suratman

Pramudita

2023

Lecture Notes in Electrical Engineering

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Modified FMCW system for non-contact sensing of human respiration

Cited by 13 publications

References 23 publications

Radar System for Detecting Respiration Vital Sign of Live Victim Behind the Wall

Radar System for Detecting Respiration Vital Sign of Live Victim Behind the Wall

A Clutter Identification and Removal Method Based on Long Delay Lines and Cross-Correlation in Through-Wall Detection

Small Displacement Detection System of Landslide Using FMCW Radar with Phase-Detection and Change Point Detection Method

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