Under Water Communication 1 (3)1

8/3/2019 Under Water Communication 1 (3)1

http://slidepdf.com/reader/full/under-water-communication-1-31 1/24

1

WelcoWelco

meme



2

UnderwaterUnderwater

CommunicationCommunication



3

Contents

IntroductionImportance of UW communication

Traditional approach

Technology in useVector sensor

Architecture of Ocean Bottom Monitoring

Challenges

SONAR

TSUNAMETER

Applications



4

Introduction

Underwater communication is a technique

of sending and receiving message below

water.

Typical frequency: 1 Hz to 1 MHz

Hydroacoustics



5

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



6

Why is Underwater Communication

Important? Naval defence (submarines)

Ocean exploration

Understanding natural disasters (tsunami)



7

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



8

Technology In Use

Hydrophone: Converts acoustic waves into electrical energy,Cannot measure multiple scalar quantities, andhas Single Input Single Output.

HydrophoneHydrophone



9

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…



10

UW-ASN 3D Architecture for ocean

bottom monitoring



11

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



12

SONAR

SOund Navigation And Ranging

Two types of technology:

Active SONAR Passive SONAR



13

Active SONAR

Active sonar uses a sound

transmitter and a receiver

• Principle:

creates “ping”

listens “echo”



14

Passive SONAR

Passive sonar listens without transmitting.

Noise limitations

Dipping sonar deployed from a Ship



Need for Tsunami Detection System

15



16



TSUNAMETER

17



COMPONENTS

Subsea Unit –Tsunameter Surface Unit -Transceiver

18



Tsunameter–Deployment in the Bay of

Bengal

19



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



21

Applications of Underwater

CommunicationSeismic monitoring.

Pollution monitoringOcean currents monitoring

Equipment monitoring and control

Ocean explorationMarine archaeology



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

22



Thank

You23



24

AnyAnyQueries?Queries?

??

Documents

Under Water Communication 1 (3)1