M. S. Engineering College, Bangalore 2014
Centre for Excellence in
Under Water Navigation Sensors and Signal Processing
Introduction:
An optical fiber that is exposed to pressure variations undergoes deformations and changes
in refractive index. Such pressure variations impose phase modulation on a coherent light beam
passing through the fiber. Fiber optic hydrophones have
been proposed as a means to achieve high sensitivity and
low noise. Analysis of these devices considered only
variations in the index of refraction; the deformation of the
optical fiber was neglected. It can be shown; however, that
deformation (i.e., the change in length of the fiber path) is
the predominant effect. The acoustic sensitivity of optical
fiber is considered analytically. Fiber optic sensor system,
the sensor and reference fibers are shaped in loops circularly
and uniformly (mandrel), heat treated or bonded together
and embedded in a spiral pattern within a low bulk modulus
and young’s modulus in appropriate elastomer
(polyurethane). The acoustic sensitivity of the sensor has been found to be high in frequency
(0.2-2.5 KHz) and static pressure independent.
The analysis & performance evaluation of the MZI Interferometric composite concentric
optical fiber based mandrel is analysed in the
commercial available software ANSYS 11.0; this is
based on FEM nodal analysis. A static analysis of the
MZI based mandrel for hydrophone was performed
by applying a pressure of 2 Mega Pascal to depict the
real underwater environmental conditions. By the
above analysis made we achieved an improved
sensitivity near about 15 dB. The foaming layer is
more soft and flexible than the base layer that is Al,
by sandwiching the optical fiber in between the foaming layer and the outer polyurethane elastic
layer improved the sensitivity of the designed mandrel radial pressure sensitivity due to its
superior compliance.
Objectives:
The aim is to design and develop sensor and novel signal processing technique for high
sensitivity gain for weak acoustic signal in underwater communication based applications. The
aim will be accomplished with the following objectives:
• To develop a sensor to detect weak acoustic signal & enhance weak signal capability
from the sensor by Photomultiplier Tube
• To enhance the directionality of weak signal on signal processing
• Preliminary analytical study of Signal processing (fiber optic acoustic sensor)
• To create an environment to the students and trainers to gain more knowledge and
exposure to the signal processing and networking field
• To promote research activities in the cluster of engineering colleges near to the institution
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M. S. Engineering College, Bangalore 2014
To develop wrap out with the working professionals and academia to bridge gap between
the industry and institutions
To conduct workshops and seminars to both teaching faculties and students of
engineering colleges to enrich the embedded knowledge with current industrial scenario
Need and Relevance:
Currently a line of array of hydrophone working on the principle of Piezo-ceramic effect,
measures the pressure change associated with the propagation of a sound wave. The sensor
converts acoustic wave into electrical energy and is used in passive under-water systems to
detect the object present but there exists “Directional Ambiguity”. To detect both objects present
and Direction Of Arrival (DOA) underwater application have motivated the development a
“modified direction estimation algorithm” to improve the DOA estimation performance for a
weak signal with more sensitivity by using standard signal processing technique Opto-acoustic
sensors are used both to transmit and receive the
acoustic signal underwater.
The transmitting transducer must be excited by
a high-voltage signal, at its resonating frequency. Even
though the data transmission is slower compared to
other carrier signal, the low absorption characteristic
enables the carrier to travel at longer range as less
absorption presented by the carrier. This sensor can be
successfully modified to detect this “Acoustic Shear”
which will enhance the direction information. By
using “Optical Fiber” sensor can be designed to detect
direction from which a sound is coming under-water. This Directional component is an
improvement over the current technology, and enhances the capabilities of underwater vehicle.
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In India, Naval Physical & Oceanographic Laboratory (NPOL) of Defense & Research
Development Organization (DRDO) at Ernakulum is working on a similar type of
project.
China has been acquiring naval facilities along the crucial choke-points in the Indian
Ocean not only to serve its economic interests but also to enhance its strategic presence in
the region. China realizes that its maritime strength will give it the strategic leverage it
needs to emerge as the regional hegemon and a potential superpower.
India needs to build capabilities to thwart these initiatives not only in the Indian Ocean
but also have the ability to defend some of its key interests in South China Sea. A key
goal of China’s maritime build-up is access denial. But China’s maritime capabilities are
set to extend beyond access denial, into power projection in the Indian Ocean.
Similar work already carried out at a Northern group America in 2009.
With India being covered with large part of ocean on all three sides, there is a need for a
sensor technology that can be used over existing underwater vehicles to detect the
direction of arrival of underwater intrusions
Research Phase:
Centre for Excellence in under water sensors will currently work on four major projects which
would be carried out in parallel in the following phases:
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M. S. Engineering College, Bangalore 2014
The proposed project has better way to understand the underwater channel (Medium).
Signal processing algorithm for detects and direction of weak signal travelling through
the underwater channel for low frequency (0.2 – 2.5 KHz). It will helpful to detect the
anti-submarine, ammunition and surveillance purpose.
Underwater ultrasonic communication has received much attenuation as their application;
have begun to shift from military toward commercial. Underwater communication differs
considerably from other types of signal propagation - both in terms of the physics and
technology involved, and the applications that use it. This project explores one possible
method of communicating underwater: using low-frequency acoustic waves.
The properties of the channel (water) mean that conventional ultrasonic techniques are
only partially applicable. Even though the data transmission is slower compared to other
carrier signal, the low absorption characteristic enables the carrier to travel at longer
range as less absorption presented by the carrier.
This algorithm keeps promise that it can be successfully modified to detect this
“Acoustic Shear” which will enhance the direction information and by using “unique
algorithm” to create a beam forming that detect a direction from which a sound is coming
under-water. This Directional component is an improvement over the current technology
–much like a microphone listen to sound in the air.
Manpower Requirement:
R&D centre will create state-of-the-art facility with sophisticated hardware and software
resources to carry out research activities in Under water Sensors. The centre will be headed by
eminent professor with experience in sensor technology, research scholars will be hired as
interns for two years and will form the core team in sensors research. The centre will hire
talented and experience engineers and also groom young scholars, undergraduates to actively
pursue the set objectives and demonstrate significant progress in Under Water Sensor
Technology.
Infrastructure Available/Requirements:
MSEC will provide space of 4000 sq. ft., for setup of software computing facility, hardware
based experimental facility, discussion room and staff room.
The hardware and software resources required for CFE:
• Matlab/Simulink/Real-Time Workshop, MS Visual C++ and MS Office on Unix and
Windows platforms.
• Photo multiplier
• Sound projector low frequency flex tensional transducer
• Function generator
• Laser kit
• Coupler
• Splitter
• Optical fiber
• N9000A CXA Signal analyzer
• ANSYS(Mechanical)
• Intel Core i7 Processor
• Intel 67 Mother Board Chipset
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M. S. Engineering College, Bangalore 2014
8 GB Crossair RAM
Nvdia 650 GT Graphics Card
Cooler Master Cabinet
Corssair 450 W SMPS
LG 24X DVD Writer
Wireless Microsoft Combo KB & Mouse
20" LG full HD Monitor
Deliverables:
The centre for excellence in Under Water Sensor Technology will be able to deliver the
following every academic year:
• We would Publish the paper on this project
• We would expand provide the hardware to the students and help them to understand the
software (coding) part.
• We will conduct workshops and seminars to both teaching faculties and students of
engineering colleges to enrich the embedded knowledge with current industrial scenario.
• We will provide workshops and create an environment to the students and trainers to gain
more knowledge and exposure to the signal processing and networking field.
• We will Train the trainer programme
• We will promote research activities in the cluster of engineering colleges near to the
institution
• We will develop wrap out with the working professionals and academia to bridge gap
between the industry and institutions.
Contact Details:
Prashil M Junghare
Assoc. Professor, Dept of ECE
MS Engineering College
Mail ID: [email protected]
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