Enhanced Technique for Accurate Localization and Life-Sign Detection of Human Subjects Using Beam-Steering Radar Architectures

• Published in: IEEE transactions on biomedical engineering Vol. 72; no. 2; pp. 552 - 564
• Main Authors: Mercuri, Marco, Sacco, Giulia, Hornung, Rainer, Visser, Huib, Lorato, Ilde, Pisa, Stefano, Veltri, Pierangelo, Dolmans, Guido
• Format: Journal Article
• Language: English
• Published: United States IEEE 01.02.2025; The Institute of Electrical and Electronics Engineers, Inc. (IEEE); Institute of Electrical and Electronics Engineers
• Subjects: 2-D localization; Algorithms; Beam steering; beam-steering radars; Chirp; Continuous radiation; Engineering Sciences; Environmental monitoring; Frequency dependence; Frequency measurement; Frequency scanning; health monitoring; Heart rate; Heart Rate - physiology; Human subjects; Humans; Information processing; Internet of medical things; Localization; Location awareness; Monitoring; Monitoring, Physiologic - instrumentation; Monitoring, Physiologic - methods; Parameters; Radar; Radar - instrumentation; Radar antennas; Radar detection; Radar range; Radar signal processing; Radar tracking; radar-based physiological measurement techniques; remote people monitoring; Signal generation; Signal processing; Signal Processing, Computer-Assisted - instrumentation; single-input and single-output radar; SISO (control systems); Smart buildings; Spectral analysis; Spectrum analysis; Two dimensional analysis; Vital Signs - physiology; vital signs monitoring; Location awareness; Chirp; Radar; Radar antennas; Radar signal processing; Frequency measurement; Monitoring
• ISSN: 0018-9294; 1558-2531; 1558-2531
• DOI: 10.1109/TBME.2024.3463199

In this work, we propose a signal processing technique for beam-steering radar architectures allowing concurrent two-dimensional (2-D) localization and vital signs monitoring of human subjects. We demonstrated it by using a single-input single-output (SISO) frequency-modulated continuous wave (FMCW) radar which integrates two frequency-scanning antennas (FSAs). This method is capable of isolating the Doppler signal generated by each single subject from the contributions of all the reflections in the monitored environment. This allows determining the number of individuals in the room and accurately measuring their vital signs parameters (respiration and heart rates) and 2-D positions (range and azimuth information). The spectral analysis, the data matrix generation and the signal processing technique are detailed and discussed. Experimental results demonstrated the feasibility of the proposed approach, showing the ability in determining the number of subjects present in the room, in accurately measuring and tracking over time their vital signs parameters, and in 2-D localization with errors within the limits of the radar range and angular resolutions. Practical applications arise for healthcare, Hospital 4.0, Internet of Medical Things (IoMT), ambient assisted living, smart buildings and through-wall sensing.