Po/Mec-Based Scattering Model for Complex Objects on a Sea Surface

Baussard, Alexandre; Rochdi, Majid; Khenchaf, Ali

doi:10.2528/pier10083005

Cited by 46 publications

(33 citation statements)

References 30 publications

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“…The Doppler spectrum of backscattered echoes provides much more valuable information than the mere radar backscattering cross section, thus the study of the Doppler spectral characteristics from dynamic oceanic surfaces has been receiving great attention for its myriad applications in research areas such as target detection [1][2][3][4][5][6][7], remote sensing in marine environment, etc. [8][9][10].…”

Section: Introductionmentioning

confidence: 99%

Investigation on Doppler Spectral Characteristics of Electromagnetic Backscattered Echoes From Dynamic Nonlinear Surfaces of Finite-Depth Sea

Nie¹,

Min²,

Geng³

et al. 2012

PIER

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Abstract-The Doppler spectral characteristics of electromagnetic backscattered echoes from dynamic nonlinear surfaces of finite-depth sea is investigated with the second-order small-slope approximation (SSA-II). The revised nonlinear hydrodynamic choppy wave model (CWM) combining with an experiment-verified shoaling coefficient is utilized to model the finite-depth sea wave profiles, and the simulated surfaces of finite-depth sea show steeper crests and more flat troughs as depth decreases. First, Comparison of the Doppler spectra for linear sea surfaces and nonlinear choppy sea surfaces shows that nonlinear hydrodynamic effect greatly enhances the Doppler shift and the Doppler spectrum bandwidth, and the predicted results agree well with the rigorous numerical model data. The Doppler spectra of backscattered echoes from finite-depth sea with different depths are further evaluated. At small incident angles, the Doppler shifts and the spectra bandwidths are much lower for shallower sea, and the opposite situation can be gradually observed for increased incident angles. This indicates that the nonlinear wave-wave interactions among waves occur more frequently in finite-depth sea and the long waves will be suppressed while shorter wind waves will be boosted in shallower water. Moreover, the dependence of the Doppler spectral characteristics on polarization is also discussed.

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Section: Introductionmentioning

confidence: 99%

Investigation on Doppler Spectral Characteristics of Electromagnetic Backscattered Echoes From Dynamic Nonlinear Surfaces of Finite-Depth Sea

Nie¹,

Min²,

Geng³

et al. 2012

PIER

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“…The wedge scattering has been fully studied with diffraction theories. This paper uses the method of equivalent currents (MEC) [36] to calculate wedge scattering field E wedge pq E wedge…”

Section: Non-bragg Scattering Of Breaking Wavementioning

confidence: 99%

Investigation of Low-Grazing-Angle Microwave Backscattering From Threedimensional Breaking Sea Waves

Luo¹,

Zhang²,

Wang³

et al. 2011

PIER

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Abstract-The microwave backscattering of the sea surface is investigated with the wedge-shaped breaking waves for the super events at low grazing angles (LGA). According to the relationship between the wave breaking and the whitecap, the finite three-dimensional wedges are utilized to approximately model the breaking waves, of which the spatial distribution is simulated with whitecap coverage. The phasemodified two-scale method (TSM) and method of equivalent currents (MEC) are used to calculate the surface and volume scattering of sea surface and breaking waves respectively. The sea spikes in LGA are observed by this model, and the strong directionality is caused by the breakers. Considering the Bragg phase velocity, orbital motion of facets and wind drift, the Doppler spectrum is simulated with the time series of sea clutter. Included the breaking waves, the scattering model indicates that the enhanced non-Bragg scattering leads to the extended Doppler spectrum width. The numerical results agree with the measured data well at LGA. Compared with the statistical models, the complex physical mechanism of the sea scattering is explicitly described in this paper.

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“…The problem of combinative target-surface, which is the case that this paper mainly handles, cannot be dealt with RT-based multi-path method in [17] because the targets are not detached. The last kind of research is to employ high frequency techniques [18,19], and this paper mainly contributes to this territory in time domain other than frequency domain in [18,19]. Time-domain high frequency methods are rarely reported in literatures discussing composite scattering from target above rough surface, although timedomain low frequency methods are reported, such as finite difference in time domain (FDTD) [20][21][22][23] and time-domain integral equation (TDIE) method [24].…”

Section: Introductionmentioning

confidence: 99%

Time-Domain Iterative Physical Optics Method for Analysis of Em Scattering From the Target Half Buried in Rough Surface: Pec Case

Li¹,

Wei²,

He³

et al. 2011

PIER

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Abstract-In this paper, time-domain physical optics (TDPO) method is extended to its iterative version (TDIPO) to consider the coupling effects between two regions, and the latter is employed to investigate electromagnetic scattering from three dimensional target half-buried by a two dimensional rough surface. By using iterative scheme, more accurate transient response reflected from combinative target with multi-scattering effects would be obtained than that by using TDPO alone. The TDIPO could also be enhanced by time-domain equivalent edge current (TDEEC) to further determine the far-field characteristics of the combinative target with rough surface. An accurate composite geometry model technique which combines 2D perfectly electrically conducting (PEC) rough surface and half-buried 3D PEC target is introduced and employed to assist the meshing work. The validity of the presented method is verified by comparing the scattering results for dihedral targets with those obtained through TDPO and finite difference in time domain (FDTD), as well as multi-level fast multiple algorithm (MLFMA). Then simulations of EM scattering from the target embedded in rough surface for different incidence directions are carried out to test the availability of TDIPO/EEC. Discussions on the effects of incidence direction and the presence of the target on the backscattering in farzone are also given.

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Po/Mec-Based Scattering Model for Complex Objects on a Sea Surface

Cited by 46 publications

References 30 publications

Investigation on Doppler Spectral Characteristics of Electromagnetic Backscattered Echoes From Dynamic Nonlinear Surfaces of Finite-Depth Sea

Investigation on Doppler Spectral Characteristics of Electromagnetic Backscattered Echoes From Dynamic Nonlinear Surfaces of Finite-Depth Sea

Investigation of Low-Grazing-Angle Microwave Backscattering From Threedimensional Breaking Sea Waves

Time-Domain Iterative Physical Optics Method for Analysis of Em Scattering From the Target Half Buried in Rough Surface: Pec Case

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