Arrival-time fluctuations of coherent reflections from surface gravity water waves

Badiey, Mohsen; Eickmeier, Justin; Song, Aijun

doi:10.1121/1.4871577

Cited by 8 publications

(3 citation statements)

References 13 publications

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“…Another design of upward-looking acoustic tools relies on sound scattering model to reconstruct surface spectrum moments basing on the Doppler spectrum of the reflected signal [12][13][14]. High frequency signals reverberation patterns may allow to track individual wave crests in vicinity of the transducer, as it has been reported by [15] and [16]. The mentioned tools are designed for local measurements and methods to assess waves and currents on a long range are of great interest too.…”

Section: Introductionmentioning

confidence: 99%

Surface waves prediction based on long-range acoustic backscattering in a mid-frequency range

Ermoshkin,

Kosteev,

Ponomarenko

et al. 2022

Preprint

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New data was obtained for a frequency band that had not been so well-studied for sea surface probing applications before. During the described 2-weeks sea experiment 1-3 kHz tonal pulses were emitted from a platform, located on the northern Black Sea shelf, and Doppler spectrum of reverberation was studied. We believe that this band is worth further studying due the sound propagation range is large enough to meet practical needs in coastal zone while the angle-distance resolution is quite moderate. However it is quite difficult to interpret the obtained data since backscattering spectrum shape is influenced by a series of effects and has a complicated link to wind waves and currents parameters. Backscattering of acoustical signals was received for distances around 2 nautical miles. Significant wave height, dominant wave frequency were estimated as the result of such signals processing with the use of machine learning tools. A decision-tree-based mathematical regression model was trained to solve the inverse problem. Wind waves prediction is in a good agreement with direct measurements, made on the platform, and machine learning results allow physical interpretation.

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Section: Introductionmentioning

confidence: 99%

Surface waves prediction based on long-range acoustic backscattering in a mid-frequency range

Ermoshkin,

Kosteev,

Ponomarenko

et al. 2022

Preprint

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“…The statistical distributions of received multipath fading signals in shallow water have been studied numerically and experimentally for underwater acoustic communication system design and performance analysis. [1][2][3][4][6][7][8][9][10][11][12][13][14][15] There is as yet no consensus on the fading statistics applicable in shallow water owing to various acoustical boundary conditions and applicable acoustic communication systems. However, representative statistics can be selected among these previous studies.…”

Section: Introductionmentioning

confidence: 99%

Frequency-selective fading statistics of shallow-water acoustic communication channel with a few multipaths

Bae¹,

Park²,

Kim³

et al. 2016

Jpn. J. Appl. Phys.

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The bit error rate of an underwater acoustic communication system is related to multipath fading statistics, which determine the signal-to-noise ratio. The amplitude and delay of each path depend on sea surface roughness, propagation medium properties, and source-to-receiver range as a function of frequency. Therefore, received signals will show frequency-dependent fading. A shallow-water acoustic communication channel generally shows a few strong multipaths that interfere with each other and the resulting interference affects the fading statistics model. In this study, frequency-selective fading statistics are modeled on the basis of the phasor representation of the complex path amplitude. The fading statistics distribution is parameterized by the frequency-dependent constructive or destructive interference of multipaths. At a 16 m depth with a muddy bottom, a wave height of 0.2 m, and source-to-receiver ranges of 100 and 400 m, fading statistics tend to show a Rayleigh distribution at a destructive interference frequency, but a Rice distribution at a constructive interference frequency. The theoretical fading statistics well matched the experimental ones.

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“…10 When the surface wave is smooth relative to source frequency, the interface of surface wave is considered to be partially flat and the pressure at the interface is computed using the reflection coefficient, 11 and the ray-based model can be applied as the previous works. [3][4][5][12][13][14][15] The benefit of the time-domain ray approach over the PE model is to enable tracking of the rays interacting with the surface wave causing the striation pattern. In our analysis, attenuation and scattering of sound by bubbles near the surface are not considered.…”

Section: Introductionmentioning

confidence: 99%

Emergence of striation patterns in acoustic signals reflected from dynamic surface waves

Choo

Seong

Song

2014

The Journal of the Acoustical Society of America

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A striation pattern can emerge in high-frequency acoustic signals interacting with dynamic surface waves. The striation pattern is analyzed using a ray tracing algorithm for both a sinusoidal and a rough surface. With a source or receiver close to the surface, it is found that part of the surface on either side of the specular reflection point can be illuminated by rays, resulting in time-varying later arrivals in channel impulse response that form the striation pattern. In contrast to wave focusing associated with surface wave crests, the striation occurs due to reflection off convex sections around troughs. Simulations with a sinusoidal surface show both an upward (advancing) and downward (retreating) striation patterns that depend on the surface-wave traveling direction and the location of the illuminated area. In addition, the striation length is determined mainly by the depth of the source or receiver, whichever is closer in range to the illuminated region. Even with a rough surface, the striation emerges in both directions. However, broadband (7-13 kHz) simulations in shallow water indicate that the longer striation in one direction is likely pronounced against a quiet noise background, as observed from at-sea experimental data.

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Arrival-time fluctuations of coherent reflections from surface gravity water waves

Cited by 8 publications

References 13 publications

Surface waves prediction based on long-range acoustic backscattering in a mid-frequency range

Surface waves prediction based on long-range acoustic backscattering in a mid-frequency range

Frequency-selective fading statistics of shallow-water acoustic communication channel with a few multipaths

Emergence of striation patterns in acoustic signals reflected from dynamic surface waves

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