volume | PIER Journals

Abstract

The ship Kelvin-wake models on two-dimensional (2-D) linear and nonlinear sea surfaces are combined with the second-order small-slope approximation method (SSA-II) to comparatively study the corresponding electromagnetic (EM) scattering characteristics. The nonlinear sea-surface models include the Choppy Wave Model (CWM) and the second-order Creamer model (Creamer (2)). Considering the limitations of using the ideal plane EM wave incident upon a rough sea surface of the limited size, the expressions of the scattered field and scattering amplitude are derived by utilizing the modified tapered incident field. Due to the fact that the nonlinear effects of Creamer (2) surfaces is obviously stronger than those of CWM surfaces, the bistatic normalized radar cross section (NRCS) calculated from Creamer (2) surfaces is significantly greater than that of its linear and CWM surfaces for scattering angles departing from the specular direction, and the backscattering coefficients from Creamer (2) surfaces are also the greatest except within quasi-specular (near vertical incidence) region. In addition, for the linear and nonlinear sea surfaces, the influences of different wind speeds and directions on scattering characteristics are also calculated and analyzed in detail. However, taking the ship Kelvin wakes into account, the corresponding scattering features are obviously distinct from those of the single linear and nonlinear sea surfaces. This helps to provide a basis to extract the related ship information through the scattering characteristics of ship Kelvin wakes. Also it shows that the small-slope approximation method is a very effective analysis method to deal with the EM scattering from the rough sea surface.

1. Zhao, Y. W., M. Zhang, X. Geng, and P. Zhou, "A comprehensive facet model for bistatic SAR imagery of dynamic ocean scene," Progress In Electromagnetics Research, Vol. 123, 427-445, 2012.
doi:10.2528/PIER11100910 Google Scholar

2. Ai, J., X. Qi, W. Yu, et al. "A novel ship wake CFAR detection algorithm based on SCR enhancement and normalized hough transform," IEEE Trans. on Geosci. Remote Sens., Vol. 8, No. 4, 681-685, 2011.
doi:10.1109/LGRS.2010.2100076 Google Scholar

3. Park, J.-I. and K.-T. Kim, "A comparative study on ISAR imaging algorithms for radar target identification," Progress In Electromagnetics Research, Vol. 108, 155-175, 2010.
doi:10.2528/PIER10071901 Google Scholar

4. Baussard, A. M., M. Rochdi, and A. Khenchaf, "PO/MEC-based scattering model for complex objects on a sea surface," Progress In Electromagnetics Research, Vol. 111, 229-251, 2011.
doi:10.2528/PIER10083005 Google Scholar

5. Nie, D. and M. Zhang, "Bistatic scattering analysis for two-dimensional rough sea surfaces using an angular composite model," Int. J. Remote Sens., Vol. 32, No. 24, 9661-9672, 2011.
doi:10.1080/01431161.2011.574160 Google Scholar

6. Bourlier, C. and G. Gerginc, "Microwave analytical backscattering models from randomly rough anisotropic sea surface |--- Comparison with experimental data in C and Ku bands," Progress In Electromagnetics Research, Vol. 37, 31-78, 2002. Google Scholar

7. Valenzuela, G. R., "Theories for the interaction of electromagnetic and oceanic waves |---A review," Boundary-layer Meteorology,, Vol. 13, 61-85, 1978.
doi:10.1007/BF00913863 Google Scholar

8. Jin, Y. Q., "Numerical simulation of radar surveillance for the ship target and oceanic clutters in two-dimensional model," Radio Science, Vol. 38, No. 3, 1045, 2003.
doi:10.1029/2002RS002692 Google Scholar

9. Reed, A. M. and J. H. Milgram, "Ship wakes and their radar images," Annu. Rev. Fluid Mech., Vol. 34, 469-502, 2002.
doi:10.1146/annurev.fluid.34.090101.190252 Google Scholar

10. Sun, R.-Q., M. Zhang, C. Wang, and Y. Chen, "Study of electromagnetic scattering from ship wakes on PEC sea surfaces by the small-slope approximation theory," Progress In Electromagnetics Research, Vol. 129, 387-404, 2012. Google Scholar

11. Nouguier, F. C., et al. "Scattering from nonlinear gravity waves: The `choppy wave' model," IEEE Trans. on Geosci. Remote Sens., Vol. 48, No. 12, 4184-4192, 2010.
doi:10.1109/TGRS.2010.2050694 Google Scholar

12. Creamer, D. B., F. Henyey, R. Schult, and J. Wright, "Improved linear representation of sea surface waves," J. Fluid Mech., Vol. 205, 135-161, 1989.
doi:10.1017/S0022112089001977 Google Scholar

13. Soriano, G., M. Joelson, and M. Saillard, "Doppler spectra from a two dimensional ocean surface at L-band," IEEE Trans. on Geosci. Remote Sens. , Vol. 44, No. 9, 2430-2437, 2006.
doi:10.1109/TGRS.2006.873580 Google Scholar

14. Bahar, E. and B. S. Lee, "Full wave solutions for rough-surface bistatic radar cross sections: Comparison with small perturbation," Physical Optics, Numerical and Experimental Results. Radio Science, Vol. 29, No. 2, 407-429, 1994. Google Scholar

15. Bahar, E. and B. S. Lee, "Radar scatter cross section for two-dimensional random rough surfaces-full wave solutions and comparisons with experiments," Wave in Random Media, Vol. 6, 1-23, 1996.
doi:10.1080/13616679609409792 Google Scholar

16. Vaitilingom, L. and A. Khenchaf, "Radar cross sections of sea and ground clutter estimated by two scale model and small slope approximation in hf-VHF bands," Progress In Electromagnetics Research B, Vol. 29, 311-338, 2011. Google Scholar

17. Voronovich, A. G., "Small-slope approximation in wave scattering by rough surfaces," Sov. Phys -- JETP., Vol. 62, 65-70, 1985. Google Scholar

18. Berginc, G. and C. Bourrely, "The small-slope approximation method applied to a three-dimensional slab with rough boundaries," Progress In Electromagnetics Research, Vol. 73, 131-211, 2007. Google Scholar

19. Toporkov, J. V., et al. "Numerical study of the extended Kirchhoff approach and the lowest order small slope approximation for scattering from ocean-like surfaces: Doppler analysis," IEEE Trans. on Antennas and Propagat., Vol. 50, No. 4, 417-425, 2002. Google Scholar

20. Chen, H., M. Zhang, and H.-C. Yin, "Faced-based treatment on microwave bistatic scattering of three-dimensional sea surface with electrically large ship," Progress In Electromagnetics Research, Vol. 123, 385-405, 2012. Google Scholar

Dr. Rong-Qing Sun

Prof. Min Zhang

Dr. Chao Wang

Dr. Xiao-Feng Yuan