title: Adaptive passive fathometer processing.
abstract: Recently, a technique has been developed to image seabed layers using the ocean ambient noise field as the sound source. This so called passive fathometer technique exploits the naturally occurring acoustic sounds generated on the sea-surface, primarily from breaking waves. The method is based on the cross-correlation of noise from the ocean surface with its echo from the seabed, which recovers travel times to significant seabed reflectors. To limit averaging time and make this practical, beamforming is used with a vertical array of hydrophones to reduce interference from horizontally propagating noise. The initial development used conventional beamforming, but significant improvements have been realized using adaptive techniques. In this paper, adaptive methods for this process are described and applied to several data sets to demonstrate improvements possible as compared to conventional processing.
authors.affiliation: Department of Electrical and Computer Engineering, Portland State University, Portland, Oregon 97201, USA.
authors.forename: Martin
authors.initials: M
authors.lastname: Siderius
authors.forename: Heechun
authors.initials: H
authors.lastname: Song
authors.forename: Peter
authors.initials: P
authors.lastname: Gerstoft
authors.forename: William S
authors.initials: WS
authors.lastname: Hodgkiss
authors.forename: Paul
authors.initials: P
authors.lastname: Hursky
authors.forename: Chris
authors.initials: C
authors.lastname: Harrison
mesh_terms: D000162:Acoustics / Q000295:instrumentation; D003198:Computer Simulation; D019015:Geologic Sediments; D005844:Geology / Q000295:instrumentation / Q000379:methods*; D008962:Models, Theoretical; D009038:Motion; D009622:Noise; D009792:Oceans and Seas; D011825:Radar / Q000295:instrumentation; D012623:Seawater; D012815:Signal Processing, Computer-Assisted; D013018:Sound Spectrography; D013997:Time Factors; D014159:Transducers