Abstract:

Analytical methods are used to express the dependence of low-frequency bistatic reverberation on the power and direction spectra of the time-dependent sea surface. The 3-D cross-spectral density (CSD) of the reverberation is obtained, to second order in the small-waveheight approximation, as a sum of dc and sideband terms. For numerical simulations, this theoretical formulation is applied to a model ocean consisting of a homogeneous half-space. The sensitivity of the CSD to the power spectrum of the source, the power and direction spectra of the surface, and bistatic source/receiver geometry are assessed for both the zero-Doppler components and the Bragg--Doppler sidebands. [Work supported by ONR.]