Comments: download pdf (not yet available).
Ref.: submitted to J. Acoust. Soc. Am. June 2016.
Abstract:
Bottom parameters are inverted from ship self-noise measured on a short vertical
array of vector sensors which was suspended from the stern of the vessel. The ship engines
ran for a few seconds every few minutes under control of the dynamic positioning system
to hold the vessel at a fixed position. By cross-correlating beams steered to directions of
eigenrays, the multipath arrival structure of the ship noise is emphasized even under strong
noise and tonal contamination. The correlation peak distribution versus two steered angles is
used for inferring the upward and the downward going eigenrays. Two inversion methods are
presented. One is to derive bottom reflection coefficients by utilizing the ratios of the of the
successive multipath correlation peaks. The other is conducted in the frequency domain by
matching the interference pattern of phases of the broadband cross-spectral density matrix,
where the source position and the bottom parameters are jointly estimated. Both results are
consistent with ground truth.