Low‐frequency acoustic tomography using matched field processing

1989 ◽  
Vol 86 (S1) ◽  
pp. S7-S7
Author(s):  
I. A. Tolstoy
Keyword(s):  
Low Frequency ◽  
Acoustic Tomography ◽  
Matched Field Processing

scholarly journals 200Hz low frequency source for ocean acoustic tomography.

1994 ◽  
Vol 21 (3) ◽  
pp. 146-155
Author(s):  
Toshiaki NAKAMURA ◽  
Toshio TSUCHIYA ◽  
Iwao NAKANO ◽  
Toshiyuki NAKANISHI ◽  
Ieharu KAIHOU ◽  
...  
Keyword(s):  
Low Frequency ◽  
Acoustic Tomography ◽  
Frequency Source ◽  
Ocean Acoustic Tomography

Inversion of Pressure Data on a Vertical Array for Sea Floor Geoacoustic Properties

1998 ◽  
Vol 06 (01n02) ◽  
pp. 269-289 ◽  
Author(s):  
Purnima Ratilal ◽  
Peter Gerstoft ◽  
Joo Thiam Goh ◽  
Keng Pong Yeo
Keyword(s):  
Ambient Noise ◽  
Historical Data ◽  
Low Frequency ◽  
Real Data ◽  
Vertical Array ◽  
Trial Site ◽  
Matched Field Processing ◽  
High Frequencies ◽  
Sea Floor ◽  
Line Array

Estimation of the integral geoacoustic properties of the sea floor based on real data drawn from a shallow water site is presented. Two independent inversion schemes are used to deduce these properties. The first is matched-field processing of the pressure field on a vertical line array due to a projected source. The second approach is the inversion of ambient noise on a vertical array. Matched-field processing has shown to be successful in the inversion of high quality field data. Here, we show that it is also feasible with a more practical and less expensive data collection scheme. It will also be shown that low frequency inversion is more robust to variation and fluctuation in the propagating medium, whereas high frequencies are more sensitive to mismatches in a varying medium. A comparison is made of the estimates obtained from the two techniques and also with available historical data of the trial site.

scholarly journals An Acoustic Tomography Technique for Concurrently Observing the Structure of the Atmosphere and Water Bodies

2017 ◽  
Vol 34 (3) ◽  
pp. 617-629 ◽  
Author(s):  
Anthony Finn ◽  
Kevin Rogers
Keyword(s):  
Theoretical Analysis ◽  
Sound Speed ◽  
Water Surface ◽  
Low Frequency ◽  
Sound Field ◽  
Acoustic Signals ◽  
Acoustic Tomography ◽  
Radio Waves ◽  
Surface Errors ◽  
Underwater Sensors

AbstractThe opacity of water to radio waves means there are few, if any, techniques for remotely sensing it and the atmosphere concurrently. However, both these media are transparent to low-frequency sound (<300 Hz), which makes it possible to contemplate systems that take advantage of the natural integration along acoustic paths of signals propagating through both media. This paper proposes—and examines with theoretical analysis—a method that exploits the harmonics generated by the natural signature of a propeller-driven aircraft as it overflies an array of surface and underwater sensors. Correspondence of the projected and observed narrowband acoustic signals, which are monitored synchronously on board the aircraft and by both sensor sets, allows the exact travel time of detected rays to be related to a linear model of the constituent terms of sound speed. These observations may then be inverted using tomography to determine the inhomogeneous structures of both regions. As the signature of the aircraft comprises a series of harmonics between 50 Hz and 1 kHz, the horizontal detection limits of such a system may be up to a few hundred meters, depending on the depth of the sensors, roughness of the water surface, errors due to refraction, and magnitude of the sound field generated by the source aircraft. The approach would permit temperature, wind, and current velocity profiles to be observed both above and below the water’s surface.

Acoustic tomography via matched field processing

1991 ◽  
Vol 89 (3) ◽  
pp. 1119-1127 ◽  
Author(s):  
A. Tolstoy ◽  
O. Diachok ◽  
L. N. Frazer
Keyword(s):  
Acoustic Tomography ◽  
Matched Field Processing

Low-Frequency Acoustic Tomography of a Shallow Sea by Low-Mode Pulses

2005 ◽  
Vol 51 (2) ◽  
pp. 182 ◽  
Author(s):  
A. G. Luchinin
Keyword(s):  
Low Frequency ◽  
Acoustic Tomography ◽  
Shallow Sea
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