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| Naval
Physical and Oceanographic Laboratory (NPOL) , Kochi
is one of the major R&D laboratories of Defence Research
and Development Organisation (DRDO). It was setup in
1952 as an in-house laboratory of the Indian Navy, then
called as Indian Naval Physical Laboratory (INPL), for
providing scientific support to the armed services.
Later it got re-christened as NPOL after the formation
of Defence Research and Development Organisation (DRDO)
under Ministry of Defence in 1958. Today NPOL stands
out with great pride for its outstanding achievements
and contributions in the areas of SONAR research and
development for Navy. |
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| The
core competence of NPOL is in the areas of oceanography,
electro-acoustic transducers, signal processing and
systems engineering. Commencing with Advanced Panoramic
Sonar Hull Mounted (APSOH) in 1983, NPOL has delivered
several sonar systems, such as Panchendriya, Humsa,
Mihir etc. which have been fitted on to submarines,
surface ships and airborne platforms of Indian Navy.
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| Over
the years, the institute has established several infrastructure
facilities for carrying out Defence R&D activities related
to sonar systems. |
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| INS
Sagardhwani |
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| NPOL/DRDO owns a marine
acoustic research vessel named as INS Sagardhwani. It
was indigenously built at M/s Garden Reach Shipbuilders
and Engineers Limited (GRSE), Calcutta and commissioned
in 1994. The vessel is run and maintained by the Indian
Navy for DRDO and based at Southern Naval Command, Kochi.
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| This ship has got many
special facilities for conducting underwater ocean environmental
and acoustic experiments both in shallow and deep waters.
State-of-the-art equipments are fitted onboard in order
to pursue research in ASW oceanography and acoustics.
The ship's laboratories house all relevant scientific
equipment to make high resolution oceanographic and acoustics
measurements at the sea. The ship can moor oceanographic
and acoustic buoys in shallow and deep waters. |
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| Facilities: |
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Bow and stern thrusters
- better maneuverability. |
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Reverse osmosis plants-30
ton fresh water/day. |
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Minimum radiated
noise. |
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Antivibration mounts
for machinery |
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Wooden quarter deck.
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Doctor & mini operation
theatre. |
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Helipad - helicopter
operations. |
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Inflated boat. |
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Handling Gears for
fast & safe deployment of scientific systems. |
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| Underwater
Acoustic Research Facility (UARF): |
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| This lake facility has
been established for calibrating & full-scale testing
of underwater acoustic transducers, arrays and other sub-sea
equipment like, echo sounders, velocimeters, underwater
communication systems, decoys, fish finding sonars etc.
It is located at Kulamavu (100 km away from Kochi) at
Idukki reservoir in the high-ranges of western ghats.
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| Major
Capabilities |
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Three vessels: M.V.
Kolumban (a barge), F.P.Kuravan ( a floating platform)
and M.V. Jalaprayog (a motorboat). |
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Crane and chain-pully
systems on board the barge for lifting and deploying
heavy transducer arrays for making measurements.
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A turn-table is
provided for making directivity measurements. |
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Electrical power
from shore-supply points. |
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Diesel generator
sets of 5 kVA, 15 kVA and 63 kVA. |
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| Depending upon the depth
(and range) requirements the platform can be positioned
anywhere in the reservoir and measurements can be made.
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| Materials
and Transducers-Simulated Test Centre (MATS): |
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| The Materials and Transducers-Simulated
Test Centre (MATS) available at NPOL, is the only one
of its kind in Asia-Pacific region and one of the very
few in the entire world. MATS is designed for undertaking
any static or dynamic measurements/evaluation/calibration
of any materials or sensors/ transducers for undersea
use. It can be gainfully used by a variety of people doing
research in the areas of oceanography, ocean acoustics,
marine geophysics, underwater acoustic transducers or
any other areas dealing with undersea equipment like underwater
cameras. Static as well as dynamic calibration of transducers
and other sensors can be efficiently carried out under
controlled pressure and temperature conditions. MATS provides
three pressure chambers of different sizes to cater for
various types of measurements that are required to be
simulated for ocean environment. It is also designed for
measurements at different operating frequencies. |
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| The entire system of complex
operations involving cooling, heating, pressurization
and de-pressurisation is controlled by a distributed control
system (DCS), which is virtually the brain behind the
entire system operation. The system is housed at a spacious
central control room. |
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| Specifications: |
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Anechoic Chambers |
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Cylindrical section
closed with hemispherical ends |
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Acoustic wedges
for internal lining |
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8000 mm (L) X 3000
mm (ID) |
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Two Ports - 830
mm & 500 mm (ID)3250 mm separation |
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Azimuth positioner |
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Low Frequency
Tubes |
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Seamless tubes |
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Internal surface
honed in single direction without any step |
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Tube 1 : 2000 mm
(L) X 300 mm (ID) |
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Tube 2 : 7000 mm
(L) X 200 mm (ID) |
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| The operational sequences
are built into the DCS using suitable software. All process
variables are monitored and controlled from the control
room using it. The control valves, drives and solenoid
valves are operated from the DCS. Individual sequences
and programming are implemented in the DCS for achieving
the required simulated conditions inside the chambers.
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| Acoustic
Tank Facility: |
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| This facility is for
digital calibration of underwater acoustic transducers
used in sonar systems and other under-water applications
such as ocean bottom profiling, underwater telephony,
fish finders etc. A water tank of 12 X 7.5 X 6 m size,
a positioning system and a set of sophisticated instrumentation
constitute this facility. It is situated at Naval Base,
Kochi. Special techniques have been employed taking into
consideration various requirements of calibration principles,
limitations of water medium, frequency range of operation
and type of parameter to be measured. |
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Primary calibration measurements
using reciprocity principle and dunking machine method
are adopted for very low frequencies (1 to 4 Hz) whereas
secondary calibration using comparison technique are adopted
for higher frequencies. Frequencies higher than 4 kHz,
can be covered by tone-burst method, whereas pulsed sound
method and random noise calibration method are employed
for lower frequencies.
Directivity pattern measurements can be made up to a resolution
of 0.1 degree. High power measurements on projectors are
done inside a pressurized Fibre Reinforced Plastic vessel,
which is deployed into the tank on specific needs.
A pulse tube (also known as impedance tube) is used for
evaluation of passive acoustic materials. It can be used
for evaluation of underwater acoustic properties like,
reflection, absorption, transmission etc.
Measurement of acceleration sensitivity is performed using
a vibration exciter system. Devices weighing up to 100
kg can be tested in this system over a wide frequency
bandwidth. |
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| Experimental
Fluid Dynamics Laboratory: |
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| The Experimental Fluid
Dynamics Laboratory that was established in the year 2000
as a part of the Centre for Oceanics and Optronics (COOPS),
comprises of a fluid tank (10m long X 2m wide X 1.5m deep)
where experiments on stratified fluids with state-of-art
instrumentation can be carried out. A computer controlled
mechanized trolley capable of taking payloads up to 250
kg enables scientists to conduct controlled experiments.
The fluid dynamics resulting from the controlled experiments
inside the wave tank can be photographed through a perspex
window on the side of the tank. The facility can also
be used for conducting calibrations of various instruments
under controlled conditions. |
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| Some of the
typical studies taken up in this laboratory are: |
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Surface manifestations
of hydrodynamic features generated by scaled models |
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Sub-surface hydrodynamic
features in stratified fluids |
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Stratified wake
/ wave studies |
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Turbulent dynamics |
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Sensor Encapsulation
testing |
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Pre and Post calibrations
of laser based systems |
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Oceanographic instrument
calibrations |
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Radio Frequency
link studies |
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Underwater Electric
Potential (UEP) studies |
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| Computer
Aided Design (CAD) Facility: |
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| The Computer
Aided Design (CAD) facility at NPOL provides an integrated
product development environment. Digital product definition
and simulation at this facility offers powerful design
tools for mechanical parts in realistic 3D environment.
The ability to develop digital prototype models has the
advantage of full understanding the product in its design
phase with easy links to manufacturing and analysis. The
depth and richness of the product information contained
in a digital model makes it easier to fully communicate
this information to everyone involved in the product development
process. Digital model helps to develop and evaluate multiple
design concepts. The CAD Software packages include IDEAS,
SOLIDWORKS, IRONCAD and AUTOCAD. The facility is networked
for efficient use and archiving data. |
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| Prototype
Manufacturing Facility: |
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| This facility
that actively assists prototype manufacture has implemented
CAM (Computer Aided Manufacturing) with the aid of a range
of modern machinery and expertise. Intricate prototypes
with desired accuracy and quality are fabricated in this
facility to assist faster execution of sonar project.
Direct access to Computer Aided Design data by Numerical
Controlled machines in a networked environment is being
implemented in this facility. |
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