Contemporary high-resolution sonar systems use broadband pulses and long arrays to achieve high resolution. It is important to understand effects that high-resolution sonar systems might have on quantitative measures of the scattered field due to the seafloor. A quantity called the broadband scattering cross section is defined, appropriate for high-resolution measurements. The dependence of the broadband scattering cross section, σ_bb, and the scintillation index, SI, on resolution was investigated for one-dimensional rough surfaces with power-law spectra and backscattering geometries. Using integral equations and Fourier synthesis, no resolution dependence of σ_bb was found. The incoherently averaged frequency-domain scattering cross section has negligible bandwidth dependence. SI increases as resolution increases, grazing angle decreases, and spectral strength increases. This trend is confirmed for center frequencies of 100 and 10 kHz, as well as for power-law spectral exponents of 1.5, 2, and 2.5. The hypothesis that local tilting at the scale of the acoustic resolution is responsible for intensity fluctuations was examined using a representative model for the effect of slopes (inspired by the composite roughness approximation). It was found that slopes are responsible in part for the fluctuations, but other effects, such as multiple scattering and shadowing may also play a role.

中文翻译：

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使用幂律粗糙度谱对粗糙表面散射的分辨率依赖性

当代的高分辨率声纳系统使用宽带脉冲和长阵列来实现高分辨率。重要的是要了解高分辨率声纳系统可能对海底散射场的定量测量产生的影响。定义了一个称为宽带散射横截面的量，适用于高分辨率测量。宽带散射横截面，所述的依赖性σ _BB，和闪烁指数，SI，对分辨率进行了研究用于与幂律谱和反向散射的几何形状的一维粗糙的表面。使用积分方程和傅立叶合成，没有分辨率依赖σ _BB被找到。非相干平均的频域散射截面具有可忽略的带宽依赖性。SI随着分辨率的增加，掠射角的减小和光谱强度的增加而增加。对于100和10 kHz的中心频率，以及1.5、2和2.5的幂律谱指数，都可以确认这种趋势。使用代表性模型对坡度的影响（受复合粗糙度近似启发），检验了以声学分辨率为单位的局部倾斜导致强度波动的假设。已经发现，斜率在某种程度上是造成波动的原因，但其他影响（例如多重散射和阴影）也可能起作用。