New Ray Methods in Propagation
LITTLE (ARTHUR D) INC CAMBRIDGE MA
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The object of this report is to supply the theoretical bases for certain useful and computable approximations to the problem of transmission loss in hydroacoustic propagation. These approximations involve a knowledge of two acoustic profiles, one at the emitter and the other at the receiver and only require general assumptions of the intermediate behavior of sound speed. In this sense they form a second approximation--the first approximation being the familiar one based on the assumption of an acoustic profile independent of range. The ranges are long enough to involve multiple-path transmission, caustics, and the complications produced by many convergence zones. The random factors and incomplete knowledge of the medium of transmission are not only explicitly acknowledged but are made to play a central role in the discussion they give rise to a somewhat novel model and open up possibilities of simplification of averages, etc.