UNDER WATER ACOUSTIC SENSOR NETWORKS

Ch . JAGANNATH SUBUDHI0911016304

ECE-’C’

INTRODUCTION Ocean bottom sensor nodes are deemed to enable applications for

oceanographic data collection, pollution monitoring, offshore exploration, disaster prevention, allocating resources and tactical surveillance applications.

To make these applications viable, there is a need to enable underwater communications among underwater devices.

These sensor communicate through acoustic waves which are a type of longitudinal waves that propagate by means of adiabatic compression and decompression.

UnderWater Acoustic Sensor Networks (UW-ASN) consist of a variable number of sensors and vehicles that are deployed to perform collaborative monitoring tasks over a given area.

SENSORS used

Group of sensors and vehicles deployed underwater and networked via acoustic links, performing collaborative tasksEquipments used Autonomous Underwater Vehicles (AUVs) Underwater sensors (UW-ASN)

OBJECTIVES

UNDERWATER ACOUSTIC SENSOR NETWORKS• To exploit multi hop paths• oceanographic data collection• pollution monitoring, disaster prevention etc.

AUTONOMOUS UNDERWATER VEHICLES• autonomous coordination obstacle avoidance

APPLICATIONS

Undersea explorations• Detect underwater oilfields

Disaster prevention• Monitoring ocean currents and Tsunamis

Assisted navigation• Locate dangerous rocks in shallow waters

Distributed tactical surveillance• Unwanted object detection (Navy)

CHALLENGES

Available bandwidth is limitedPropagation delayUnderwater=5 x Radio Frequency(RF)ground

High bit errors and temporary loss of connectivityLimited battery powerTendency of failure in the underwater sensors

because of corrosion

ARCHITECTURE

1.Two-dimensional UW-ASNs for ocean bottom monitoring.

2. Three-dimensional UW-ASNs for ocean column monitoring.

3. Three-dimensional networks of Autonomous Underwater Vehicles (AUVs).

1.Two-dimensional UW-ASNs for ocean bottom monitoring.

Application of 2-D, UW-ASN for ocean bottom monitoring

Typical applications may be• Environmental monitoring• Monitoring of underwater plates in tectonics region.

2.Three-dimensional UW-ASNs for ocean column monitoring

Application of 3-D, UW-ASN for ocean column monitoring

Typical application are:-

• surveillance applications • monitoring of ocean phenomena (ocean bio-

geo-chemical processes, water streams, pollution, etc).

3.Three-dimensional networks of Autonomous Underwater Vehicles

Application of 3-D networks of Autonomous Underwater Vehicles

Applications can be---• environmental monitoring • underwater resource study.

UW-ASN:DESIGN CHALLENGEs

• UWSNs vs Terrestrial Sensor Networks– Cost– Power– Memory

• Some factors that affect the design– Path loss– Noise – Propagation delayUnderwater=5 x Radio Frequency(RF)ground

CONCLUSIONS

• The ultimate objective of this paper is to encourage research efforts to lay down fundamental basis for the development of new advanced communication techniques for efficient underwater communication and networking for enhanced ocean monitoring and exploration applications.

REFERENCES [1] Images adapted from ] F. Akyildiz, D. Pompili, and T. Melodia. Underwater

Acoustic Sensor Networks: Research Challenges. Ad Hoc Networks (Elsevier), vol. 3(3), pp. 257–279, May 2005; publication,Broadband wireless networking lab school of electrical nad computer engineering,georgia institute of technology ; google images.

[2]D.Pompili ,T.Melodia , and I. F. Akyildiz , "Three-dimensional andTwo-dimensional Deployment Analysis for Underwater Acoustic Sensor Networks," submitted for journal publication , Broadband wireless networking lab school of electrical nad computer engineering,georgia institute of technology.

[3] I. F. Akyildiz ,D.Pompili , and T.Melodia. Underwater Acoustic Sensor Networks: Research Challenges. Ad Hoc Networks (Elsevier), vol. 3(3), pp. 257–279, May 2005.

[4] J. Proakis, J. Rice, E. Sozer, and M. Stojanovic, “Shallow water acoustic networks,” in Encyclopedia of Telecommunications, J. G. Proakis, Ed.John Wiley and Sons, 2003.

[5]-L. Freitag and M. Stojanovic, “Acoustic communications for regional undersea observatories,” in Proceedings of Oceanology International,London, U.K., mar 2002.

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