08-10-2016, 04:32 PM
A NEW REVOLUTIONARY SYSTEM TO DETECT THE HUMAN BEINGS BURIED UNDER EARTHQUAKE RUBBLE BY MICROPROCESSOR OR MICROCONTROLLER
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ABSTRACT
“Thousand of persons killed as a cause of
earthquake”. The above words aren’t the headlines of
the newspaper but such news come after the disaster
destroyed the field. The disaster in the New York
City at ‘World Trade Center’ claimed lives of more
than 5000 people. It was said if survivors has been
found and rescue earlier the numbers of victims have
been lower. There is no end to the number of lives
lost as the result of such disasters as landslides,
collapsed tunnels and avalanches.
A new revolutionary system is develop for the search
and rescue of victims trapped under the rubble of
collapsed building during the earthquake or other
disasters. The proposed system utilizes L-band
frequency which is able to detect respiratory and
heart fluctuations. The operation principle is based
on Doppler frequency shift of the electromagnetic
wave reflected from the buried victim. The schematic
diagram of microwave Transmitting/Receiving (T/R)
and clutter cancellation subsystem are included in
this report. In this report various parts of a
microwave life detection system such as antenna,
directional coupler, and splitter has been discussed.
By advent of this system the world death rate as a
cause of an earthquake may decrease to greater
extent.
INTRODUCTION
Most of the victims of earthquake or other natural
disasters in the various parts of the worlds are trapped
under rubble of the collapsed buildings. A detection
of the victims can save his life. As in the radar
application, the phase of the incident wave can be
changed due the body vibrations. Depending upon
this fact “A Revolutionary System to Detect Human
Being Buried under the Rubble” used to trap the
buried victims under earthquake rubble or collapsed
buildings by the utilization of microwave radio
frequency has been design.
1.1 Need of life detection system over
conventional system
Existing ways to detect the human being under the
earthquake rubble and collapsed buildings are
utilization of the dogs, optical devices and acoustic
life detectors and the rescue robot .But the dogs can
detect the dead persons and this occupies the precious
time which can be utilize to detect alive victims. Due to the fact that lower frequency will be more
capable of detecting vital signs through very thick
rubble, so frequency of an electromagnetic wave
needs to be in the L-band or S-band range, For this Also, the optical devices have a limited number of
degree of freedom, require expert operators .
Rescue Robot can navigate deep into the rubble to
search for victim by the use of temperature sensor but
they are unable to trap once they go out of
range..Information about the location of buried
person would be of great value for the rescue
personnel, since it would help to reduce the time of
operation and thus, help to save more lives. There is a
need to construct a life detection system which can
detect buried victims under earthquake or building
debris most efficiently and as possible in short time.
Such kinds of problems have been efficiently solved
considering continuous wave or ultra wideband
radars which offer good localization and spatial
accuracy.In rescue mission and also in some
surveillance operations there is not only the need of
detect life signals but also the identification of people
in a given area, to facilitate rescue team operations in
case of emergencies. This task can be complied with
through the wall surveillance techniques.
1.2 Principle of Working:
The principle of detection is firstly, microwave is sent
through rubble to detect vital signs of life. Microwave is
having the property to penetrate through barriers and
would reflect back from some objects. These objects
include humans. When the beam hits the body, the
signal reflected with an additional modulation created
by movement of heart and lungs. So, the reception of
modulated signals shows the presence of alive human
inside the rubble. With the modulated signal there are
some signal (commonly known as clutter signal) which
are reflected from the immobile object such as rubble or
debris. Thus in order to maintain a high sensitivity for
this application, the clutter wave reflected from the
rubble or the surface of the ground has to be cancelled
as thoroughly as possible. For this an automatic clutter
cancellation system is used. A microwave life detection
system operated on the radio frequency was proposed in
the 1985.This system detects the body oscillations occur
due the breathing and heartbeat fluctuations. The system
includes the additional subsystem to cancel the
unwanted signals receive from the motionless objects
such as rubble
LITERATURE REVIEW
Images of events causing damage in which people have
been trapped or buried under rubble serve as constant
reminders of the vulnerability of the places where we
live and work. To conduct rapid rescue operations,
emergency forces all over the world need timely
information on the exact position of people trapped or
buried under rubble, information on the risk of collapse
of debris and standardized intervention procedures as
well as information on the state of the victims’ health.
2.1 History
Collapse of man-made structures, such as buildings
and bridges, occur with varying frequency across the
world. In such a case, survived human beings are
often trapped in the cavities created by collapsed
building material. The concept of microwave life
detection system was emerged with the development
in the systems for rescue operation. Initial dogs were
used to detect presence of human then acoustic
detectors and robot radar come into existence. But
these systems are having major drawbacks.
The history of “Revolutionary System to detect
Human Being Buried Under the Rubble” starts with
K. M. Chen who brings out the concept of detection
of buried victims using microwave beam in 1985.
After the detailed study of microwave signals and
Doppler’s effect, Ku Mem chen had been proposed
including the basic principle for the operation of life
detection system in 1991.
A Low Power Hand-Held Microwave Device for the
Detection of Trapped Human Personnel by W. S.
Haddad in 1997. The device, called the Rubble
Rescue Radar (RRR) incorporates Micropower
Impulse Radar technology which was developed at
Lawrence Livermore National Laboratory over the
few years. In 2003 P. K. Banerjee and A. Sengupta
proposed the basic block diagram for the clutter
cancellation system. In 2004, there was a concept of
three band radar system proposed by M. Bimpas.
The researcher put their effort to study the various
effect various bands of microwave signals and
depending upon this, a system which detect human
being with ka-band with double sidebands have been
proposed, in 2006. It states that a short wavelength of
ka-band increases the sensitivity of antenna which
will detect the small body vibration . A paper on
‘An X-band microwave life detection system’ has
been presented by Huey Ru in 2007. In this paper
author present the idea of detecting human being
located behind the wall using a microwave signal .
The phase change of a reflected microwave signal
will provide the precious information about the
buried victim’s heartbeat as well as breathing
A rescue radar system is proposed by M. Donelli in
2011. In radar system a SAW oscillator is used to
generate 10GHz frequency signals. While receiving
through patch antenna the signal is process by the
ICA (Independent Component Algorithm).
.MATERIAL AND METHOD
This section includes detail description of block
diagram of “Revolutionary System to Detect Human
Being Buried under the Rubble.” Also with this there
is explanation of various parts of microwave system.
The working of clutter cancellation system is
included in this section.
3.1 Block Diagram :
The microwave life detection system has four major
components. They are a microwave circuit which
generates, amplifies and distributes microwave
signals to different microwave components. A dual
antenna system, which consists of two antennas,
energized sequentially. A microwave controlled
clutter cancellation system, which creates an optimal
signal to cancel the clutter from the rubble.
3.1.1 A Microwave Circuit:
The microwave circuit in the fig.2 consists of phase
locked oscillator, directional couplers and circulator.
The phase locked oscillator is used to generate a very
stable electromagnetic wave of 2GHz range. The
SAW (Surface Acoustic Wave) oscillator can
generates 1150 MHz frequency with output power
400mW.
Power dividers and directional couplers are passive
devices used in the field of radio technology. They
couple part of the transmission power in a
transmission line by a known amount out through
another port, often by using two transmission lines
set close enough together such that energy passing
through one is coupled to the other. In microwave life
detection system 10 dB and 3dB couplers are used.
10dB coupler is used to divide the power into 1/10th
and 9/10th part while 3dB coupler divides power into
two equal parts.
3.1.2 Antenna:
The dual antenna system has two antennas, which are
energized sequentially by an electronically controlled
microwave single-pole double-throw (SPDT) switch.
The switch turns on and off at a frequency of 100 Hz
which is much higher than the frequency range of the
breathing and heartbeat signals between 0.2 Hz and 3
Hz. Thus, we can consider that the two antennas
essentially sample their respective objects at the same
time. In this dual-antenna system, the two antenna
channels are completely independent.
The algorithm and flowcharts for the antenna is as
follows:
1. Initially the switch is kept in position 1 (signal is
transmitted through the antenna 1)
2. Wait for some predetermined sending time, Ts
3. Then the switch is thrown to position 2 (signal is
received through the antenna 2)
4. Wait for some predetermined receiving time, Tr
5. Go to step 1
6. Repeat the above procedure for some
predetermined time, T.
3.1.3 A Clutter Cancellation Circuit:
. In any remote sensing instrument the clutter caused by
undesirable objects surrounding the detectable subject
must be cancel to the optimum level. The clutter
canceller forms the heart of life detection system. It
consists of Programmable Phase Shifters, Programmable
Attenuator, a RF Amplifier a Microprocessor based
control unit
3.1.3.1 Canceller Operation:
The clutter signal is passed through a detector as shown
in fig. 4 which outputs a DC voltage of few tens mV.
Then it is amplified by an operational amplifier and fed
to A/D converter whose outputted to the Port A of
microprocessor. The output port C and port B are
connected to the phase attenuator and phase shifter
respectively. The controller uses different combination
of attenuation and phase shifting to achieve optimum
level.
CONCLUSION
A life-detection system with a microprocessor-based
automatic clutter cancellation subsystem can be
invented for special rescuing robots. This system can
operates at 2-G Hz and it will be used remotely to
detect the breathing and heartbeat signals of alive
subjects through rubble or some other barriers about
3ft in thickness. The microprocessor-based automatic
clutter- canceling increases the efficiency of system.
The clutter canceller uses an adjustable attenuator
and phase shifter to cancel the transmitting power
leakage from the circulator and background reflection
clutter to enhance the detecting sensitivity of the
weak vital signals.
We believe that through the development of similar
and related techniques for life detection system, it
will be possible to overcome the current fundamental
problems in detecting buried victims and save many
precious lives.