Through-the-sensor sub-bottom imaging using the self-noise of an autonomous underwater vehiclea)

This work demonstrates the feasibility of performing through-the-sensor (TTS) sub-bottom imaging using low-frequency ([100 Hz-1kHz]) self-noise generated by the propulsion of an autonomous underwater vehicle (AUV) acting as a source of opportunity. The self-noise was recorded by a short towed horizontal line array (11.4 m aperture) by the same AUV while it operated ∼35 m above the seabed along a range-dependent section at the New England shelf break. The seabed and sub-bottom layers imaged by this TTS method were found to be consistent with the images simultaneously obtained at higher frequency [2.5-4.5 kHz] using a conventional active source mounted on the AUV.