Simulation of the sea clutter signal by using digital signal processing (DSP) platform for radar performance testing is an prospective and widely used technique in radar engineering application. Based on the digital signal processor TMS320C6748 as the hardware platform and the autoregressive model, a method of generating non-stationary K distributed sea clutter is proposed. In DSP realization of the non-stationary sea clutter sequence simulation, its amplitude usually satisfies the K distribution, and the amplitude envelope and Doppler spectral center frequency will change with time. The simulation results show that the probability distribution and time-frequency characteristics of the sea clutter are in good agreement with the theoretical values.
A weighted multi-path model for the composite electromagnetic (EM) scattering and SAR image application of sea surface with a ship target is presented according to the distribution characteristics of specular reflection facets on a deterministic rough sea surface. This model reasonably includes the influence of non-negligible roughness of sea surface in the coupling scattering calculation, which could avoid the error caused by planar approximation in the traditional four-path model. Numerical simulation results show that the entire simulator could provide a preliminary prediction on the radar cross sections (RCS) for the composite scene with electrically large size. In addition, the total scattering contribution contains both the amplitude and phase information of the scattering facets on the composite ship-sea surface, which can be effectively applied in the scattering characteristics identification of ship target on the sea surface and SAR image simulation.
The electromagnetic (EM) scattering features of radar scattered echoes from nearshore sea surfaces are investigated using the second-order small-slope approximation (SSA-II). The joint influences of wind fetch and water depth on the normalized radar cross section (NRCS) of and Doppler spectra for echoes from nearshore sea surfaces are mainly studied. The numerical results show that with a further increasing fetch, the excess of NRCS for small depth sea over that for deeper sea increases, and Doppler spectral features are also intensely influenced by nonlinear interactions between waves in the large wind fetch and small water depth marine environment. These both indicate that the effects of the finite depth are more prominent with increasing wind fetch, especially for HH polarization.
In this paper, the Monte Carlo Method is applied to study the vegetation scattering and its low-grazing characteristics. Based on the Two-layer canopy scattering model, phase difference of the discrete scatterers and volume-surface scattering interaction are taken into account, the scattering coefficient is simulated by the Monte Carlo method. The numerical results are compared with the experiments and the corresponding theory, which justify the backscattering enhancement and grazing incidence characteristic properly.