Accurate Heart Rate Detection from On-Body Continuous Wave Radar Sensors Using Wavelet Transform

Abstract The pulse arrival time (PAT), pre-ejection period (PEP) and pulse transit time (PTT) are calculated using on-body continuous wave radar (CWR), Photoplethysmogram (PPG) and Electrocardiogram (ECG) sensors for wearable continuous systolic blood pressure (SBP) measurements. The CWR and PPG sensors are placed on the sternum and left earlobe respectively. This paper presents a signal processing method based on wavelet transform and adaptive filtering to remove noise from CWR signals. Experimental data are collected from 43 subjects in various static postures and 26 subjects doing 6 different exercise tasks. Two mathematical models are used to calculate SBPs from PTTs/PATs. For 38 subjects participating in posture tasks, the best cumulative error percentage (CEP) is 92.28% and for 21 subjects participating in exercise tasks, the best CEP is 82.61%. The results show the proposed method is promising in estimating SBP using PTT. Additionally, removing PEP from PAT leads to improving results by around 9%. The CWR sensors present a low-power, continuous and potentially wearable system with minimal body contact to monitor aortic valve mechanical activities directly. Results of this study, of wearable radar sensors, demonstrate the potential superiority of CWR-based PEP extraction for various medical monitoring applications, including BP measurement.

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Automotive Frequency Modulated Continuous Wave Radar Interference Reduction Using Per-Vehicle Chirp Sequences

Sensors ◽

10.3390/s18092831 ◽

2018 ◽

Vol 18 (9) ◽

pp. 2831 ◽

Cited By ~ 7

Author(s):

Youn-Sik Son ◽

Hyuk-Kee Sung ◽

Seo Heo

Keyword(s):

Continuous Wave ◽

Signal Interference ◽

Radar Signal ◽

Driver Assistance ◽

Interference Reduction ◽

Fmcw Radar ◽

Radar Sensors ◽

Vehicle To Vehicle ◽

Radar Systems ◽

Wave Radar

Recently, many automobiles adopt radar sensors to support advanced driver assistance system (ADAS) functions. As the number of vehicles with radar systems increases the probability of radar signal interference and the accompanying ghost target problems become serious. In this paper, we propose a novel algorithm where we deploy per-vehicle chirp sequence in a frequency modulated continuous wave (FMCW) radar to mitigate the vehicle-to-vehicle radar interference. We devise a chirp sequence set so that the slope of each vehicle’s chirp sequence does not overlap within the set. By assigning one of the chirp sequences to each vehicle, we mitigate the interference from the radar signals transmitted by the neighboring vehicles. We confirm the performance of the proposed method stochastically by computer simulation. The simulation results show that the detection and false alarm performance is improved significantly by the proposed method.

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Evaluation of a robust correlation-based true-speed-over-ground measurement system employing a FMCW radar

International Journal of Microwave and Wireless Technologies ◽

10.1017/s1759078719000928 ◽

2019 ◽

Vol 11 (7) ◽

pp. 686-693 ◽

Cited By ~ 1

Author(s):

Torsten Reissland ◽

Bjoern Lenhart ◽

Johann Lichtblau ◽

Michael Sporer ◽

Robert Weigel ◽

...

Keyword(s):

Continuous Wave ◽

Field Measurements ◽

Proof Of Concept ◽

Fmcw Radar ◽

Radar Sensors ◽

Novel Approach ◽

Ground Measurement ◽

Wave Radar ◽

24 Ghz

AbstractThis paper presents a novel approach for the determination of True-Speed-Over-Ground for trains. Speed determination is accomplished by correlating the received signals of two side-looking radar sensors. The theoretically achievable precision is derived. Test measurements are done in two different scenarios to give a proof of concept. Thereafter a series of field measurements is performed to rate the practical suitability of the approach. The results of the measurements are thoroughly evaluated. The test and field measurements are carried out using a 24 GHz frequency modulated continuous wave radar.

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From Tumor Targeting to Speech Monitoring: Accurate Respiratory Monitoring Using Medical Continuous-Wave Radar Sensors

IEEE Microwave Magazine ◽

10.1109/mmm.2014.2308763 ◽

2014 ◽

Vol 15 (4) ◽

pp. 66-76 ◽

Cited By ~ 16

Keyword(s):

Tumor Targeting ◽

Continuous Wave ◽

Respiratory Monitoring ◽

Radar Sensors ◽

Wave Radar ◽

Speech Monitoring

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On fundamental operating principles and range-doppler estimation in monolithic frequency-modulated continuous-wave radar sensors

Facta universitatis - series Electronics and Energetics ◽

10.2298/fuee1804547m ◽

2018 ◽

Vol 31 (4) ◽

pp. 547-570

Author(s):

Vladimir Milovanovic

Keyword(s):

Continuous Wave ◽

High Volume ◽

Intermediate Frequency ◽

System Level ◽

Order Effects ◽

Wave Band ◽

Design Strategies ◽

Radar Sensors ◽

Trade Offs ◽

Wave Radar

The diverse application areas of emerging monolithic noncontact radar sensors that are able to measure object?s distance and velocity is expected to grow in the near future to scales that are now nearly inconceivable. A classical concept of frequency-modulated continuous-wave (FMCW) radar, tailored to operate in the millimeter-wave (mm-wave) band, is well-suited to be implemented in the baseline CMOS or BiCMOS process technologies. High volume production could radically cut the cost and decrease the form factor of such sensing devices thus enabling their omnipresence in virtually every field. This introductory paper explains the key concepts of mm-wave sensing starting from a chirp as an essential signal in linear FMCW radars. It further sketches the fundamental operating principles and block structure of contemporary fully integrated homodyne FMCW radars. Crucial radar parameters like the maximum unambiguously measurable distance and speed, as well as range and velocity resolutions are specified and derived. The importance of both beat tones in the intermediate frequency (IF) signal and the phase in resolving small spatial perturbations and obtaining the 2-D range-Doppler plot is pointed out. Radar system-level trade-offs and chirp/frame design strategies are explained. Finally, the nonideal and second-order effects are commented and the examples of practical FMCW transmitter and receiver implementations are summarized.

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Performance Evaluation of Vibrational Measurements through mmWave Automotive Radars

Remote Sensing ◽

10.3390/rs13010098 ◽

2020 ◽

Vol 13 (1) ◽

pp. 98

Author(s):

Gianluca Ciattaglia ◽

Adelmo De Santis ◽

Deivis Disha ◽

Susanna Spinsante ◽

Paolo Castellini ◽

...

Keyword(s):

Continuous Wave ◽

Vibrational Analysis ◽

Frequency Measurement ◽

Laser Vibrometer ◽

Radar Sensors ◽

Large Bandwidth ◽

Wave Radar ◽

Measurement Results ◽

Reference Laser ◽

Automotive Radars

Thanks to the availability of a significant amount of inexpensive commercial Frequency Modulated Continuous Wave Radar sensors, designed primarily for the automotive domain, it is interesting to understand if they can be used in alternative applications. It is well known that with a radar system it is possible to identify the micro-Doppler feature of a target, to detect the nature of the target itself (what the target is) or how it is vibrating. In fact, thanks to their high transmission frequency, large bandwidth and very short chirp signals, radars designed for automotive applications are able to provide sub-millimeter resolution and a large detection bandwidth, to the point that it is here proposed to exploit them in the vibrational analysis of a target. The aim is to evaluate what information on the vibrations can be extracted, and what are the performance obtainable. In the present work, the use of a commercial Frequency Modulated Continuous Wave radar is described, and the performances achieved in terms of displacement and vibration frequency measurement of the target are compared with the measurement results obtained through a laser vibrometer, considered as the reference instrument. The attained experimental results show that the radar under test and the reference laser vibrometer achieve comparable outcomes, even in a cluttered scenario.

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Command Recognition Using Binarized Convolutional Neural Network with Voice and Radar Sensors for Human-Vehicle Interaction

Sensors ◽

10.3390/s21113906 ◽

2021 ◽

Vol 21 (11) ◽

pp. 3906

Author(s):

Seunghyun Oh ◽

Chanhee Bae ◽

Jaechan Cho ◽

Seongjoo Lee ◽

Yunho Jung

Keyword(s):

Neural Network ◽

Convolutional Neural Network ◽

Continuous Wave ◽

Low Complexity ◽

Cluttered Environments ◽

Radar Sensors ◽

Wave Radar ◽

Single Voice ◽

Neural Network Algorithm ◽

Single Sensor

Recently, as technology has advanced, the use of in-vehicle infotainment systems has increased, providing many functions. However, if the driver’s attention is diverted to control these systems, it can cause a fatal accident, and thus human–vehicle interaction is becoming more important. Therefore, in this paper, we propose a human–vehicle interaction system to reduce driver distraction during driving. We used voice and continuous-wave radar sensors that require low complexity for application to vehicle environments as resource-constrained platforms. The proposed system applies sensor fusion techniques to improve the limit of single-sensor monitoring. In addition, we used a binarized convolutional neural network algorithm, which significantly reduces the computational workload of the convolutional neural network in command classification. As a result of performance evaluation in noisy and cluttered environments, the proposed system showed a recognition accuracy of 96.4%, an improvement of 7.6% compared to a single voice sensor-based system, and 9.0% compared to a single radar sensor-based system.

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