under water communication 1 (3)1
TRANSCRIPT
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WelcoWelco
meme
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UnderwaterUnderwater
CommunicationCommunication
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Contents
IntroductionImportance of UW communication
Traditional approach
Technology in useVector sensor
Architecture of Ocean Bottom Monitoring
Challenges
SONAR
TSUNAMETER
Applications
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Introduction
Underwater communication is a technique
of sending and receiving message below
water.
Typical frequency: 1 Hz to 1 MHz
Hydroacoustics
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Why using sound as communication
medium in UW-ASN?Radio waves
Optical waves
Acoustic transmission is better suited to
water than air
Speed of sound in water ~ 1500m/sec
Speed of sound in air ~ 340m/sec
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Why is Underwater Communication
Important? Naval defence (submarines)
Ocean exploration
Understanding natural disasters (tsunami)
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Traditional approach for
ocean-bottom monitoringUses sensors to record data
Disadvantages:
Real time monitoring is not possible.
No interaction b/w onshore control systems
and the monitoring instruments.
failures or misconfigurations may occur
Limited storage capacity
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Technology In Use
Hydrophone: Converts acoustic waves into electrical energy,Cannot measure multiple scalar quantities, andhas Single Input Single Output.
HydrophoneHydrophone
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What is Vector Sensor?
Measures Pressure ,velocity & acceleration of acoustic
fieldSingle Input Multiple Output
More Efficient and Compact Size
Therefore Vector Sensor is much more better than
other receivers…
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UW-ASN 3D Architecture for ocean
bottom monitoring
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Challenges
Battery Power is limited
Limited available bandwidth
Channel characteristicsUW sensors are prone to failures because of
fouling, corrosion, etc
Mobility
The ocean can be as deep as 10 km
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SONAR
SOund Navigation And Ranging
Two types of technology:
Active SONAR Passive SONAR
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Active SONAR
Active sonar uses a sound
transmitter and a receiver
• Principle:
creates “ping”
listens “echo”
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Passive SONAR
Passive sonar listens without transmitting.
Noise limitations
Dipping sonar deployed from a Ship
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Need for Tsunami Detection System
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TSUNAMETER
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COMPONENTS
Subsea Unit –Tsunameter Surface Unit -Transceiver
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Tsunameter–Deployment in the Bay of
Bengal
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Working principle
• The system consists of
a seabed pressure
monitoring
transponder,a surface buoy with a data
collection unit that
passes the acoustic
message to a satellitetelephone system and
then onwards to the
shore base.20
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Applications of Underwater
CommunicationSeismic monitoring.
Pollution monitoringOcean currents monitoring
Equipment monitoring and control
Ocean explorationMarine archaeology
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REFERENCES[1] Shan Jiang,Stavros Georgakopoulos,“Electromagnetic Wave Propagation into
Fresh
Water”, Vol.3, June 2nd, 2011 , pp.261-266.
[2] Nick Street,David Mould, “ Tsunami Detection System,”.
[3] Christian Meinig, Scott E. Stalin, Alex I. Nakamura, “Real-Time Deep-Ocean
Tsunami Measuring,Monitoring, and Reporting System: The NOAA DART II
Description and Disclosure,”
[4] Milica Stojanovic, “ Underwater Communications,”Journal of Physics,Conference
Series 178, 2009.
[5] J. H. Goh, A. Shaw, A. I. Al-Shanmma’a, “Underwater Wireless Communication
System,” IEEE Transactions on Antennas and Propagtion, Vol. 52, No. 11, November
2004, pp. 2843- 2849.[6] I. F. Akyildiz, D. Pompili, and T. Melodia, “Underwater acoustic sensor networks:
research challenges”, Elsevier, Ad Hoc Networks 3 (2009), 257–279.
[8] www.sonardyne.com
[7] www.noaanews.noaa.gov.htm
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Thank
You23