Mid-Frequency Propagation Modeling Using the Waveguide Invariant.

摘要

Random variability in shallow water will induce variability in a propagating acoustic field. The long-term goal of this research is to quantify how random variability in the ocean environment translates into random variability in the acoustic field and the associated signal processing algorithms in the midfrequency (1-10 kHz) band. In the present funding cycle, the emphasis is on the waveguide invariant. Constructive and destruction interference is an inevitable consequence of multipath acoustic propagation in shallow water. If the ocean environment is sufficiently benign, the so-called waveguide invariant describes the resulting interference pattern. The waveguide invariant, usually designated as beta, has traditionally been regarded as a low-frequency phenomenon. The objectives of the present work are twofold: first, to extend the waveguide invariant concept so it may be incorporated into midfrequency signal processing algorithms, and second to quantify the limitations on these algorithms imposed by shallow-water internal waves.