Mathematical simulation of remote detection of human breathing and heartbeat by multifrequency radar on the background of local objects reflections

Abstract

The mathematical description of signal processing basic stages in multifrequency radar intended for detection of human breathing and heartbeat is given. Cross-correlation functions of different kinds of the multifrequency probing signals, modelling optimum processing of impulses are compared in view of resolution, levels of lateral lobes and presence of diffractive maxima. The model of multifrequency radar signal taking into account breath and palpitation of the person is offered. For remote allocation of person's breath and heartbeat realizations with selection on range cells the spectral analysis in each range element is used. Such a selection besides definition of range up to the living human allows excluding reflections from motionless and inactive local objects, available in other range cells.

A Feasibility Study for Life Signs Monitoring via a Continuous-Wave Radar

“…A multifrequency radar designed at the Remote Sensing Laboratory (Bauman Moscow State Technical University) was used in the experiment [9,11]. The radar has the main technical parameters reported in Table 1.…”

“…The second data-processing approach is designed with the aim to gain information not only about the frequency behavior of the life signs but even about the range of the investigated subject [9,11]. The procedure can be summarized according to the step below.…”

“…The first step allows to build the range-frequency matrix [9]; this matrix contains all possible signal reflections including ones from the motionless objects (MOs), located in different range cells. These objects are the cause of static clutter.…”

“…The multifrequency bioradar with a quadrature receiver has been designed at the Remote Sensing Laboratory, Bauman Moscow State Technical University with the aim to carry out remote monitoring of movement activity, breathing, and pulse of human heart [9].…”

“…The second approach aims at providing information not only about the frequency of life signs but also at gaining information about the range of the investigated target by getting range-frequency matrix. Separation of respiration and heartbeat signals was made by application of rejection filtration to corresponding line of range-frequency matrix [9,11].…”