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UNDERSEA TECHNOLOGY 



81 



Propagation of sound energy through an ocean environment is a complex process 

 and one that is not fully understood. The Navy acoustical oceanography effort con- 

 tinues to gain working knowledge of the effect of the ocean environment on under- 

 water sound propagation. 



developments are undertaken not only to improve the equipments them- 

 selves but also to measure the environmental characteristics of the world's 

 oceans so the operators may select the appropriate mode of operation. 



On June 30, 1966, Projects Artemis and Trident were combined, and 

 the research and development program and the existing facilities (the Tudor 

 Hill Laboratory, Bermuda, Argus Island, and the USNS MISSION CAPIS- 

 TRANO) were transferred into an acoustic surveys project. The Navy is 

 conducting research and ocean engineering leading toward the development 

 of equipment and systems to meet specific requirements for ASW surveil- 

 lance. 



The current program emphasizes research and at-sea experimentation to 

 resolve acoustic, environmental, and engineering uncertainties prior to the 

 development of subsystems and/or systems. In general, investigations are 

 being pursued in the areas of wave-front behavior, target characteristics, 

 ambient noise, propagation, reverberation, signal processing, design of un- 

 derseas structures and components, and undersea power transmission tech- 

 niques. 



Typical oceanographic efforts carried out under the project are acoustic 

 surveys, in areas of interest to determine bottom roughness, depth, and 

 composition, surface temperature throughout the year, sound velocity pro- 

 files in the immediate area and as a function of season, ambient noise direc- 

 tivity, spectrum, coherence, energy levels and statistics, reverberant reflec- 

 tors and scatterers, and the energy level and coherence of their returns. 



