The simulation of the SAR image of a ship wake

A computer simulation of L-band SAR (synthetic aperture radar) images of surface-ship wakes is described, and the simulation results are compared to actual Seasat, satellite-borne SAR imagery. The model used in the simulation accounts for both the disturbance produced in the water by the moving ship and the influence of the background sea. The radar scatter from the wake is modeled using the Bragg mechanism. A two-scale model of the sea surface is employed in which it is assumed that the small-wavelength Bragg waves are modulated by the larger-scale ambient sea and wake fluctuations. The larger-scale fluctuations are important because they can alter the local angle of incidence and thus cause a tilt modulation in the scattering coefficient. Several components of the wake are modeled: the ambient waves, the Kelvin wake, and the turbulent wake. The model can produce long turbulent wakes, which may be bright or dark, depending on the geometry of the ship, radar, and wind, and it can produce Kelvin wakes.< >