Electromagnetic scattering from a stack of two one-dimensional rough surfaces separating homogeneous media is modeled with rigorous integral formulation solved by the method moments. We present an efficient numerical for computing field scattered such layers, in reflection as well transmission. call this propagation-inside-layer expansion (PILE) due to its straightforward physical interpretation. To our knowledge, it first able handle problems configuration huge number unknowns. study...

This paper introduces a “refractivity from clutter” (RFC) approach with an inversion method based on pregenerated database. The RFC exploits the information contained in radar sea clutter return to estimate refractive index profile. Whereas initial efforts are algorithms giving good accuracy involving high computational needs, present is learning machine algorithm order obtain real‐time system. shows feasibility of technique least squares support vector by comparing it genetic simulated and...

In the domain of electromagnetic wave propagation in presence rough surfaces, Rayleigh roughness criterion is a widely- used means to estimate degree considered surface. this paper, extended case layers. Thus, it provides an interesting qualitative tool for estimating

A fast, exact numerical method based on the of moments (MM) is developed to calculate scattering from an object below a randomly rough surface. Déchamps et al. [J. Opt. Soc. Am. A23, 359 (2006)] have recently PILE (propagation-inside-layer expansion) for stack two one-dimensional interfaces separating homogeneous media. From inversion impedance matrix by block (in which matrices each interface and coupling are involved), this allows one separately exactly multiple-scattering contributions...

The approaches developed by Wagner (1966) and Smith (1967) for computing the shadowing properties from a one-dimensional randomly stationary surface are investigated an arbitrary uncorrelated height slope probability density function (PDF) extended to two-dimensional in monostatic bistatic configurations. Bourlier et al. (see Progress Electromagnetic Research, J. A. Kong, Ed., vol.27, p.226-87, 2000) have expressed, Brown's (1980) work , average functions, surface, whatever assumed PDF. They...

In this paper, a fast exact numerical method, based on the method of moments, is developed to calculate scattering by an object above rough surface. N. Déchamps et al. have recently PILE (Propagation-Inside-Layer Expansion) for stack two one-dimensional interfaces separating homogeneous media. This allows us separately and exactly multiple contributions inside layer. done with decomposition block impedance matrix (the inverse each interface coupling matrices are involved). The purpose paper...

An efficient hybrid KA-EFIE formulation is deployed to analyze the electromagnetic (EM) scattering from a 3-D perfectly electric conducting (PEC) object buried beneath 2-D dielectric rough surface. In this approach, and magnetic current densities on surface are analytically obtained through current-based Kirchhoff approximation (KA), whereas density rigorously determined by solving field integral equation (EFIE) using Galerkin's method of moments (MoM) with Rao-Wilton-Glisson (RWG) basis...

In this paper, the first-order small slope approximation is applied to a rough sea surface with non-Gaussian statistics, for which third- and fourth-order statistics are taken into account in calculation of radar cross section. From Cox Munk distribution, higher order statistic moments derived, behaviors corresponding correlation functions assumed. We show that fourth (related peakedness or kurtosis) isotropic, whereas third skewness) has behavior as cos(/spl psi/), where /spl psi/ wave...

Radar cross section (RCS) is usually defined in the far-field zone. In this case, RCS independent of range radar from object. However, several scenarios, like for military applications or measurements led anechoic chambers, object located near-field From physical optics (PO) approximation and some simplifying assumptions, paper presents useful analytical formulae monostatic canonical shape perfectly-conducting objects at oblique incidence angles. The are then compared with PO integral, which...

[1] Refractivity from clutter (RFC) retrieves the radio frequency refractive conditions along a propagation path by inverting measured radar sea return. In this paper, real-time RFC technique is proposed called "Improved Best Fit" (IBF). It based on finding environment with best fit to one of many precomputed, modeled returns for different environments in database. The method improved considering mean slope factor, and physical considerations are added: smooth variations azimuth duct height...

An asymptotic method is described for predicting the bistatic normalized radar cross section of a rough homogeneous layer made up two surfaces. The model based on iteration Kirchhoff approximation to calculate fields scattered by layer, and reduced high-frequency limit in order obtain numerical results rapidly. Shadowing effects, significant large incidence or scattering angles, are taken into account through use shadowing functions. applicable moderate surface roughnesses having small...

The problem of hydrodynamic modeling the surfaces oil films at sea is treated by using physical models, namely, model local balance and Elfouhaily spectrum for describing clean surface. Then, this refined contaminated seas makes it possible to derive electromagnetic considering thin on Two simplifying approaches in dealing with complex double-layer are described, called "thin-layer" "classical" approaches. These two approaches, both having advantage reducing a single-layer problem, compared...

Radar Cross Section is most of the time defined in far field. In that case, RCS totally independent range between radar and target. However, several kinds military scenario, it can be more realistic to deal with target nearfield scattering characteristics. Using a relation define near-field RCS, this communication proposes simple approximated analytical formulas express monostatic perfectly conducting flat targets observed normal incidence. † Also IREENA, Polytech’Nantes, La Chantrerie, rue...

In civil engineering, conventional methods used to estimate the thickness of pavements assume flat interfaces. contrast, this study uses a rigorous electromagnetic method called propagation-inside-layer-expansion (PILE) simulate radar backscattered signal at nadir from rough pavement made up two interfaces separating homogeneous media. The statistical distribution first echoes is studied by comparison with default case, together their frequency behaviour. Within scope road survey ground...

In this article, the fields scattered by coated cylinders, a rough layer, and an object below surface are computed efficient propagation-inside-layer-expansion (PILE) method combined with physical optics (PO) approximation to accelerate calculation of local interactions on non-illuminated scatterer, which is assumed be perfectly conducting. The PILE based moments, impedance matrix two scatterers then inverted blocks from Taylor series expansion inverse Schur complement. Its main interest...

This paper presents the numerical method, generalized propagation-inside-layer expansion (GPILE), to calculate scattered electromagnetic field by any stratified 1-D medium composed of three random rough interfaces separating homogeneous media. GPILE is a generalization which considers only two interfaces. Both methods rely on rigorous implementation Maxwell equations, with simple matrix formulation and have straightforward physical interpretation. In particular, this method allows us...

The small slope approximation (SSA) and the Kirchhoff approach (KA) are applied to prediction of microwave sea surface backscatter for both Ku C bands various wind speeds incident angles. Numerical results obtained assuming a non-directional wavenumber spectrum compared with azimuthally averaged Cand Ku-band radar backscattering data. KA can be rigorously perfectly-conducting surface, whereas dielectric either order one (KA1) or stationary phase (SP) method used. data incidence angles...

Abstract When solving electromagnetic rough-surface scattering problems, the effect of shadowing by surface roughness often needs to be considered, especially as illumination angle approaches grazing incidence. This paper presents Ricciardi-Sato, well Wagner and Smith formulations for calculating monostatic bistatic statistical functions from a one-dimensional rough stationary surface, which are valid an uncorrelated Gaussian process with infinite length. In this paper, these extended...

In this paper, recent asymptotic backscattering models are compared for one-dimensional multiscale dielectric sea surfaces with Gaussian statistics and by considering the Elfouhaily et al. height spectrum. We focus on calculations of normalized radar cross sections (NRCS) obtained from weighted local curvature approximations (WCA LCA), recently published Elfouhaily, first- second-order small slope approximation (SSA(1) plus SSA(2) denoted as SSA), developed Voronovich. Voronovich (2002 Waves...

This paper is devoted to the forward radar propagation over clean and contaminated seas, using Ament model by taking shadowing effect into account. The well-known Rayleigh parameter, which characterizes degree of roughness a corrugated surface for case reflection on rough surface, presented. Then, it extended transmission through layer two interfaces. parameter allows then calculate oil slicks sea surfaces, model. Moreover, improved Numerical results seas are presented, compared that seas.

The objective of this paper is to develop innovative approaches obtain analytical expressions the radar cross section (RCS) perfectly conducting random rough surfaces under physical optics (PO) approximation. led take into account specific geometrical properties considered calculate their RCS. reduce computing time with respect numerical PO technique, which requires two integrations. All developed are validated by comparison a commercial code (the multilevel fast multi-pole method (MLFMM)...