Simulation of a Wideband Radar Echo of a Target on a Dynamic Sea Surface

Unlike a generally rough ground surface, the sea surface varies over time. To analyze the impact of the motion of sea waves on the synthetic aperture radar (SAR) image of a target, the wideband echo simulation method based on a frequency domain is used. For the wideband echo, the electromagnetic (EM) scattering properties of the main frequency components are analyzed by the simulation method. Based on the EM scattering properties, the echo can be accurately simulated by using the inverse fast Fourier transformation (IFFT). Combined with the flight path of the radar, the echo of each pulse can be simulated to obtain the SAR image. The correct evaluation of the EM scattering properties is indispensable to the acquisition of an accurate SAR image. For complex targets, such as ships, the multiple scattering effects have a significant influence on the EM scattering properties. Thus, a rectangular wave beam-based geometrical optics and physical optics (GO/PO) method is introduced to calculate the EM scattering properties, which is more efficient than the traditional GO/PO. The GO/PO method is suitable to simulate SAR images in which the EM scattering properties of each pulse need to be calculated. With these methods, the SAR images of the target on the sea surface are simulated. Based on the comparison of the SAR images between a static and dynamic sea surface, it is found that the region corresponding to the target is blurred and the texture of the dynamic sea is blurrier. The impact of multiple scattering and sea wave motion on target recognition are also analyzed with the SAR images that were generated under different conditions. Some strong scattering points appear when multiple scattering effects are considered. It is also found that the texture of the SAR images, corresponding to the sea surface, changes with the synthetic aperture time.

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Effects of multiple scattering encountered for various small-angle scattering model functions

Journal of Applied Crystallography ◽

10.1107/s1600576718010816 ◽

2018 ◽

Vol 51 (5) ◽

pp. 1455-1466 ◽

Cited By ~ 5

Author(s):

Grethe Vestergaard Jensen ◽

John George Barker

Keyword(s):

Multiple Scattering ◽

Small Angle ◽

Gaussian Function ◽

Small Angle Scattering ◽

Radius Of Gyration ◽

Scattering Function ◽

Angle Scattering ◽

Scattering Effects ◽

The Impact ◽

Multiple Scattering Effects

In small-angle scattering theory and data modeling, it is generally assumed that each scattered ray – photon or neutron – is only scattered once on its path through the sample. This assumption greatly simplifies the interpretation of the data and is valid in many cases. However, it breaks down under conditions of high scattering power, increasing with sample concentration, scattering contrast, sample path length and ray wavelength. For samples with a significant scattering power, disregarding multiple scattering effects can lead to erroneous conclusions on the structure of the investigated sample. In this paper, the impact of multiple scattering effects on different types of scattering pattern are determined, and methods for assessing and addressing them are discussed, including the general implementation of multiple scattering effects in structural model fits. The modification of scattering patterns by multiple scattering is determined for the sphere scattering function and the Gaussian function, as well as for different Sabine-type functions, including the Debye–Andersen–Brumberger (DAB) model and the Lorentzian scattering function. The calculations are performed using the semi-analytical convolution method developed by Schelten & Schmatz [J. Appl. Cryst. (1980). 13, 385–390], facilitated by analytical expressions for intermediate functions, and checked with Monte Carlo simulations. The results show how a difference in the shape of the scattering function plotted versus momentum transfer q results in different multiple scattering effects at low q, where information on the particle mass and radius of gyration is contained.

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Evaluation of Radar Multiple-Scattering Effects from a GPM Perspective. Part I: Model Description and Validation

Journal of Applied Meteorology and Climatology ◽

10.1175/jam2424.1 ◽

2006 ◽

Vol 45 (12) ◽

pp. 1634-1647 ◽

Cited By ~ 20

Author(s):

A. Battaglia ◽

M. O. Ajewole ◽

C. Simmer

Keyword(s):

Monte Carlo ◽

Numerical Model ◽

Multiple Scattering ◽

Optical Thickness ◽

Radiative Transfer Equation ◽

Model Description ◽

Pencil Beam ◽

Scattering Effects ◽

The Impact ◽

Multiple Scattering Effects

Abstract A numerical model based on the Monte Carlo solution of the vector radiative transfer equation has been adopted to simulate radar signals. The model accounts for general radar configurations such as airborne/spaceborne/ground based and monostatic/bistatic and includes the polarization and the antenna pattern as particularly relevant features. Except for contributions from the backscattering enhancement, the model is particularly suitable for evaluating multiple-scattering effects. It has been validated against some analytical methods that provide solutions for the first and second order of scattering of the copolar intensity for pencil-beam/Gaussian antennas in the transmitting/receiving segment. The model has been applied to evaluate the multiple scattering when penetrating inside a uniform hydrometeor layer. In particular, the impact of the phase function, the range-dependent scattering optical thickness, and the effects of the antenna footprint are considered.

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MULTIPLE SCATTERING EFFECTS IN THE COBALT K-EDGE EXAFS OF METAL CARBONYL COMPLEXES

Le Journal de Physique Colloques ◽

10.1051/jphyscol:19868110 ◽

1986 ◽

Vol 47 (C8) ◽

pp. C8-589-C8-592

Author(s):

N. BINSTED ◽

S. L. COOK ◽

J. EVANS ◽

R. J. PRICE ◽

G. N. GREAVES

Keyword(s):

Multiple Scattering ◽

Metal Carbonyl ◽

Carbonyl Complexes ◽

Metal Carbonyl Complexes ◽

Scattering Effects ◽

Multiple Scattering Effects

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Multiple Scattering Effects of an Ensemble of Irregularly Shaped Particles.

10.21236/ada175420 ◽

1986 ◽

Author(s):

Cavour Yeh

Keyword(s):

Multiple Scattering ◽

Scattering Effects ◽

Multiple Scattering Effects

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Realizing Target Detection in SAR Images Based on Multiscale Superpixel Fusion

Sensors ◽

10.3390/s21051643 ◽

2021 ◽

Vol 21 (5) ◽

pp. 1643

Author(s):

Ming Liu ◽

Shichao Chen ◽

Fugang Lu ◽

Mengdao Xing ◽

Jingbiao Wei

Keyword(s):

Synthetic Aperture Radar ◽

False Alarm ◽

False Alarm Rate ◽

Target Detection ◽

Synthetic Aperture ◽

False Alarms ◽

Sar Image ◽

Constant False Alarm Rate ◽

Sar Images ◽

Complex Scenes

For target detection in complex scenes of synthetic aperture radar (SAR) images, the false alarms in the land areas are hard to eliminate, especially for the ones near the coastline. Focusing on the problem, an algorithm based on the fusion of multiscale superpixel segmentations is proposed in this paper. Firstly, the SAR images are partitioned by using different scales of superpixel segmentation. For the superpixels in each scale, the land-sea segmentation is achieved by judging their statistical properties. Then, the land-sea segmentation results obtained in each scale are combined with the result of the constant false alarm rate (CFAR) detector to eliminate the false alarms located on the land areas of the SAR image. In the end, to enhance the robustness of the proposed algorithm, the detection results obtained in different scales are fused together to realize the final target detection. Experimental results on real SAR images have verified the effectiveness of the proposed algorithm.

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