scholarly journals Vital Signal Detection Using Multi-Radar for Reductions in Body Movement Effects

Sensors ◽  
2021 ◽  
Vol 21 (21) ◽  
pp. 7398
Author(s):  
Ah-Jung Jang ◽  
In-Seong Lee ◽  
Jong-Ryul Yang
Keyword(s):  
Signal Detection ◽  
Continuous Wave ◽  
Signal To Noise Ratio ◽  
Body Movement ◽  
Phase Variation ◽  
Maximum Velocity ◽  
The Body ◽  
Wave Radar ◽  
The Difference ◽  
Correlated Signals

Vital signal detection using multiple radars is proposed to reduce the signal degradation from a subject’s body movement. The phase variation in the transceiving signals of continuous-wave radar due to respiration and heartbeat is generated by the body surface movement of the organs monitored in the line-of-sight (LOS) of the radar. The body movement signals obtained by two adjacent radars can be assumed to be the same over a certain distance. However, the vital signals are different in each radar, and each radar has a different LOS because of the asymmetric movement of lungs and heart. The proposed method uses two adjacent radars with different LOS to obtain correlated signals that reinforce the difference in the asymmetrical movement of the organs. The correlated signals can improve the signal-to-noise ratio in vital signal detection because of a reduction in the body movement effect. Two radars at different frequencies in the 5.8 GHz band are implemented to reduce direct signal coupling. Measurement results using the radars arranged at angles of 30°, 45°, and 60° showed that the proposed method can detect the vital signals with a mean accuracy of 97.8% for the subject moving at a maximum velocity of 53.4 mm/s.

scholarly journals American Sign Language Recognition Using an FMCW Wireless Sensor (Student Abstract)

2020 ◽  
Vol 34 (10) ◽  
pp. 13781-13782
Author(s):  
Yuanqi Du ◽  
Nguyen Dang ◽  
Riley Wilkerson ◽  
Parth Pathak ◽  
Huzefa Rangwala ◽  
...  
Keyword(s):  
American Sign Language ◽  
Sign Language ◽  
Continuous Wave ◽  
The Body ◽  
Wireless Sensor ◽  
American Sign ◽  
Language Recognition ◽  
Sign Language Recognition ◽  
Wave Radar ◽  
Cloud Points

In today's digital world, rapid technological advancements continue to lessen the burden of tasks for individuals. Among these tasks is communication across perceived language barriers. Indeed, increased attention has been drawn to American Sign Language (ASL) recognition in recent years. Camera-based and motion detection-based methods have been researched extensively; however, there remains a divide in communication between ASL users and non-users. Therefore, this research team proposes the use of a novel wireless sensor (Frequency-Modulated Continuous-Wave Radar) to help bridge the gap in communication. In short, this device sends out signals that detect the user's body positioning in space. These signals then reflect off the body and back to the sensor, developing thousands of cloud points per second, indicating where the body is positioned in space. These cloud points can then be examined for movement over multiple consecutive time frames using a cell division algorithm, ultimately showing how the body moves through space as it completes a single gesture or sentence. At the end of the project, 95% accuracy was achieved in one-object prediction as well as 80% accuracy on cross-object prediction with 30% other objects' data introduced on 19 commonly used gestures. There are 30 samples for each gesture per person from three persons.

scholarly journals Searching for Survivors through Random Human-Body Movement Outdoors by Continuous-Wave Radar Array

PLoS ONE ◽  
2016 ◽  
Vol 11 (4) ◽  
pp. e0152201 ◽  
Author(s):  
Chuantao Li ◽  
Fuming Chen ◽  
Fugui Qi ◽  
Miao Liu ◽  
Zhao Li ◽  
...  
Keyword(s):  
Human Body ◽  
Continuous Wave ◽  
Body Movement ◽  
Wave Radar

The Research of Phase Method of Laser Ranging Measurement System

2012 ◽  
Vol 479-481 ◽  
pp. 632-635 ◽  
Author(s):  
Jing Huang ◽  
Bao Quan Dong
Keyword(s):  
Measurement System ◽  
Continuous Wave ◽  
Phase Variation ◽  
Frequency Measurement ◽  
Phase Method ◽  
Laser Ranging ◽  
Time Interval ◽  
Overall Design ◽  
Phase Discrimination ◽  
The Difference

The phase method of laser ranging modulates laser by using a continuous wave, calculating the time interval indirectly through the phase variation of the modulation wave when it propagates between the measured targets, and make out the measured distance. This paper uses the principle of phase method of laser ranging, proposes the overall design scheme of phase method of laser measurement system which achieves the distance measurement by using methods of the difference frequency measurement and digital phase discrimination as well as the microcontroller. It also analysis the system possible errors from many aspects, puts forward the appropriate measures to improve the accuracy of the measurement.

scholarly journals Archimedean Spiral Antenna Calibration Procedures to Increase the Downrange Resolution of a SFCW Radar

2008 ◽  
Vol 2008 ◽  
pp. 1-7 ◽  
Author(s):  
Ioan Nicolaescu ◽  
Piet van Genderen
Keyword(s):  
Time Domain ◽  
Continuous Wave ◽  
Phase Variation ◽  
Antenna System ◽  
Spiral Antenna ◽  
Multiple Reflections ◽  
Archimedean Spiral ◽  
Wave Radar ◽  
Time Domain Response ◽  
The Time Domain

This paper deals with the calibration procedures of an Archimedean spiral antenna used for a stepped frequency continuous wave radar (SFCW), which works from 400 MHz to 4845 MHz. Two procedures are investigated, one based on an error-term flow graph for the frequency signal and the second based on a reference metallic plate located at a certain distance from the ground in order to identify the phase dispersion given by the antenna. In the second case, the received signal is passed in time domain by applying an ifft, the multiple reflections are removed and the phase variation due to the time propagation is subtracted. After phase correction, the time domain response as well as the side lobes level is decreased. The antenna system made up of two Archimedean spirals is employed by SFCW radar that operates with a frequency step of 35 MHz.

scholarly journals Low Probability of Intercept Triangular Modulated Frequency Modulated Continuous Wave Signal Characterization Comparison using the Spectrogram and the Scalogram

2017 ◽  
pp. 37-47
Author(s):  
Daniel L. Stevens ◽  
Stephanie A. Schuckers
Keyword(s):  
Continuous Wave ◽  
Signal To Noise Ratio ◽  
Time Frequency ◽  
Novel Approach ◽  
Wave Radar ◽  
Time Frequency Localization ◽  
Low Probability ◽  
Low Probability Of Intercept ◽  
Radar Signals ◽  
Continuous Wave Signal

Digital intercept receivers are currently moving away from Fourier-based analysis and towards classical time-frequency analysis techniques for the purpose of analyzing low probability of intercept radar signals. This paper presents the novel approach of characterizing low probability of intercept frequency modulated continuous wave radar signals through utilization and direct comparison of the Spectrogram versus the Scalogram. Two different triangular modulated frequency modulated continuous wave signals were analyzed. The following metrics were used for evaluation: percent error of: carrier frequency, modulation bandwidth, modulation period, chirp rate, and time-frequency localization (x and y direction). Also used were: percent detection, lowest signal-to-noise ratio for signal detection, and plot (processing) time. Experimental results demonstrate that overall, the Spectrogram produced more accurate characterization metrics than the Scalogram. An improvement in performance may well translate into saved equipment and lives.

scholarly journals mGEODAR—A Mobile Radar System for Detection and Monitoring of Gravitational Mass-Movements

Sensors ◽  
2020 ◽  
Vol 20 (21) ◽  
pp. 6373
Author(s):  
Anselm Köhler ◽  
Lai Bun Lok ◽  
Simon Felbermayr ◽  
Nial Peters ◽  
Paul V. Brennan ◽  
...  
Keyword(s):  
High Resolution ◽  
Real Time ◽  
Continuous Wave ◽  
Signal To Noise Ratio ◽  
Mass Movement ◽  
Radar System ◽  
Gravitational Mass ◽  
Mass Movements ◽  
Low Resolution ◽  
Wave Radar

Radar measurements of gravitational mass-movements like snow avalanches have become increasingly important for scientific flow observations, real-time detection and monitoring. Independence of visibility is a main advantage for rapid and reliable detection of those events, and achievable high-resolution imaging proves invaluable for scientific measurements of the complete flow evolution. Existing radar systems are made for either detection with low-resolution or they are large devices and permanently installed at test-sites. We present mGEODAR, a mobile FMCW (frequency modulated continuous wave) radar system for high-resolution measurements and low-resolution gravitational mass-movement detection and monitoring purposes due to a versatile frequency generation scheme. We optimize the performance of different frequency settings with loop cable measurements and show the freespace range sensitivity with data of a car as moving point source. About 15 dB signal-to-noise ratio is achieved for the cable test and about 5 dB or 10 dB for the car in detection and research mode, respectively. By combining continuous recording in the low resolution detection mode with real-time triggering of the high resolution research mode, we expect that mGEODAR enables autonomous measurement campaigns for infrastructure safety and mass-movement research purposes in rapid response to changing weather and snow conditions.

scholarly journals Characterisation of human gait using a continuous-wave radar at 24 GHz

2008 ◽  
Vol 6 ◽  
pp. 67-70 ◽  
Author(s):  
C. Hornsteiner ◽  
J. Detlefsen
Keyword(s):  
Moving Objects ◽  
Continuous Wave ◽  
The Body ◽  
Human Gait ◽  
Radar Signal ◽  
Body Parts ◽  
Mean Velocity ◽  
Time Frequency ◽  
Wave Radar ◽  
Wide Range

Abstract. Human locomotion consists of a complex movement of various parts of the body. The reflections generated by body parts with different relative velocities result in different Doppler shifts which can be detected as a superposition with a Continuous-Wave (CW) Radar. A time-frequency transform like the short-time Fourier transform (STFT) of the radar signal allows a representation of the signal in both time- and frequency domain (spectrogram). It can be shown that even during one gait cycle the velocity of the torso, which constitutes the major part of the reflection, is not constant. Further a smaller portion of the signal is reflected from the legs. The velocity of the legs varies in a wide range from zero (foot is on the ground) to a velocity which is higher than that of the torso. The two dominant parameters which characterise the human gait are the step rate and the mean velocity. Both parameters can be deduced from suitable portions of the spectrogram. The statistical evaluation of the two parameters has the potential to be included for discrimination purposes either between different persons or between humans and other moving objects.

scholarly journals Low Probability of Intercept Triangular Modulated Frequency Modulated Continuous Wave Signal Characterization Comparison Using the Wigner Ville Distribution and the Choi Williams Distribution

2019 ◽  
pp. 35-44
Author(s):  
Daniel L. Stevens
Keyword(s):  
Continuous Wave ◽  
Signal To Noise Ratio ◽  
Time Frequency ◽  
Novel Approach ◽  
Wave Radar ◽  
Time Frequency Localization ◽  
Low Probability ◽  
Low Probability Of Intercept ◽  
Radar Signals ◽  
Continuous Wave Signal

Digital intercept receivers are currently moving away from Fourier-based analysis and towards classical time frequency analysis techniques for the purpose of analyzing low probability of intercept radar signals. This paper presents the novel approach of characterizing low probability of intercept triangular modulated frequency modulated continuous wave radar signals through utilization and direct comparison of the Wigner Ville Distribution versus the Choi Williams Distribution. The following metrics were used for evaluation: percent error of: carrier frequency, modulation bandwidth, modulation period, chirp rate, and time-frequency localization (x and y direction). Also used were: percent detection, lowest signal-to noise ratio for signal detection, and plot (processing) time. Experimental results demonstrate that overall, the Wigner Ville Distribution produced more accurate characterization metrics than the Choi Williams Distribution. An improvement in performance may well translate into an increase in personnel safety.

Sign in / Sign up

Export Citation Format

Share Document