An Improved Facet-Based TSM for Electromagnetic Scattering From Ocean Surface

Angular Composite Facet Model with Shadowing Treatment for Backscattering from Two-Dimensional Rough Sea Surface

“…The difference for Z-buffer is probably due to the color and size recognition error of facets and the difference for FGSA is mainly due to the stochastic characteristics of surface slope. Figure 11 shows the backscattering changes when taking shadowing effects into consideration and comparisons are made with results from SDFSM and GOSSA shown in [18,36]. With consideration of shadowing effect, both VV and HH polarized scattering decrease at very large incident angles above 80°.…”

“…As Arnold [21] reminded us that an 'average' radar cross-section can change as much as 10 dB in a 1-minute interval, this is also an acceptable difference with other simulated methods. Figure 11 shows the backscattering changes when taking shadowing effects into consideration and comparisons are made with results from SDFSM and GOSSA shown in [18,36]. With consideration of shadowing effect, both VV and HH polarized scattering decrease at very large incident angles above 80 • .…”

“…Even though similar applications are likely to be much more common as the spatial resolution and temporal resolution of SAR constantly enhance, only a few facet-based methods have been proposed to deal with it. Wang and Tong [18] adopted a Facet-Based GO-SSA Model to calculate the normalized RCS from 2D sea surface with visibility factor evaluated by shadow functions [19]. Rochidi [20] applied physical optics and the method of equivalent currents to calculate the facet scattering along with back-face culling algorithm and painter's algorithm evaluating the self-shadowing and mutual shadowing effect, respectively, and then used multiple-bounce scattering mechanisms to calculate the bistatic scattering for complex objects over sea surface.…”

“…With aforementioned facet-based methods, scattering contribution from facets can be calculated efficiently and the results are accurate or acceptable. Unfortunately, most of these above approaches either did not take shadowing effects into consideration in a more practical way like shadow functions used by Wang [18] and only self-shadowing factor adopted by Nie [22], or brought about an increase in computational complexity using finer facets by Arnold-Bos [21,24].…”

Effective approach to generate electrically large rough surfaces and the application to EM scattering problems

“…Generally, the sampling interval is always less than one-eighth of the incident wavelength when generating a surface, which leads to a large number of sample points and huge consumption of computer memory and makes it difficult to be realised on personal computers for electrically large surfaces at higher microwave bands. In order to reduce the computational burden, many improvements [12][13][14][15][16] have been made based on these methods. These research studies can be roughly divided into two categories.…”