IEEE - Aerospace and Electronic Systems - November 2019 - 33

Shah and Fioranelli

Figure 4.
General architecture for identifying people based on vital signs.

Apart from these diversities, the recording of breathing
patterns in ventilation at rest when person is in steadystate condition, normal breathing condition and abnormal
breathing episodes are examined in ventilatory chambers
[21]. This variable condition has a unique pattern and may
be due to neural system or due to electrochemical loops. It
is obvious that each person presents a specific breathing
pattern among innumerable combination of airflow and
ventilatory profiles [21]. A large set of data obtained for
hundreds of people examined over a period of time, these
profiles might lead to an unique identification of person
based on their vital signs acquired which can potentially
give another aspect to the conventional fingerprinting system. A unique-personal identification system was introduced by Rahman et al. [21] which identifies people based
on their vital signs using a continuous wave (CW) radar
system. The general architecture of the proposed system
having training and implementation stage is shown in
Figure 4.

OCCUPANCY MONITORING USING RADAR
Distinguishing multiple people in indoor environment
using radar system is a challenging task. However,
leveraging multiple antennas for radar technology, the
sensor might be able to count people and distinguish them
using various cardiovascular imprints irrespective or identifying life within the area of interest. The occupancy
monitoring using radar is possible by examining the heart
NOVEMBER 2019

rate of people present. Using angle of arrival, very similar
heart rates can be detected using single antenna, multiple
antennas, single input and single output, and multiple
inputs and multiple outputs. Estimating the angle of
arrival of signals can help in separating and classifying
people spatially in a multiple antenna environment. An Sband quadrature receiver based on Doppler radar using
coaxial components was used to detect the people within
area of interest [30]. The core idea of this work was to
build an efficient and alternate way to tune devices turn
OFF when they were not being used. Therefore, the proposed work saved large amount of electrical power which
made it into a sustainable and long-term solution for occupancy monitoring.

DAILY ROUTINE ACTIVITY RECOGNITION
Activity recognition and estimation of gait parameter are
medically essential components of remote health monitoring systems that can improve quality of life, enable
personalized treatments, acquire continual medical data
to better inform doctors of the patient well-being, reduce
health costs, and ensure rapid response to medical emergencies [31]. The radar sensing technologies can be used
to detect different kinds of gaits by extracting the range,
Doppler, amplitude, and phase information [32]. These
capabilities enable to detect daily routine activities and
classification of human gait [33] such as walking, sitting,
and standing, squatting, bending down to grab objects,

IEEE A&E SYSTEMS MAGAZINE

IEEE - Aerospace and Electronic Systems - November 2019

Table of Contents for the Digital Edition of IEEE - Aerospace and Electronic Systems - November 2019