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THEORETICAL DERIVATION OF SPATIAL CORRELATION FUNCTIONS FOR VARIOUS NOISE MODELS
NAVY UNDERWATER SOUND LAB NEW LONDON CONN
OBSERVATIONS INDICATE THAT NOISE IN THE OCEAN I A SUPERPOSITION OF AN ISOTROPIC NOISE FIELD AND AN ANISOTROPIC NOI E FIELD ORIGINATING AT THE SURFACE. Models which produce such noise fields are described, and the spatial correlation functions are ob ained. The volume noise model, which produces an isotropic noise field, consists of noise sources uniformly distributed within a sphere. A single frequency of each noise source is considered the frequency and mean square output of each are the same, the relative phases are random, and inverse spreading occurs. For a very large sphere the spatial correlation is the same as that given by Marsh for a homogeneous isotropic noise field and by the Faran and Hills noi e model, which consists of noise sources on the surface of a large sphere. The surface noise model consists of noise sources uniformly distributed on a large circular area of a plane. The noise sources are assumed to be directional in addition to having the properties listed above. The spatial correlation i obtained as a function of the directionality of the noise sources, the spacing of the receivers and their orientation with respect to the surface, and the elec rical delay. Results for the two noise models are compared in relation to signal-to-noise gain of hydrophone arrays. Author