Two-dimensional simulations of SAR imagery of ocean waves

The authors have carried out two-dimensional simulations of synthetic aperture radar (SAR) imagery of ocean waves and compared these simulations with actual images obtained during the SAXON-FPN experiment. They have simulated the imagery using measured imaging parameters and three variations of SAR imaging theory which make progressively more simplifying assumptions: time-dependent, velocity-bunching, and quasi-linear. They find that under most standard SAR imaging conditions, time-dependent and velocity-bunching models are indistinguishable. However, for long integration times the velocity bunching simulations show a smearing of the spectral peak. This effect is intensified for large R/V ratios (where R is the average range distance and V is the platform velocity). The quasi-linear formulation assumes linear imaging and fails for large R/V ratios to reproduce the low frequency behavior observed in actual imagery, due to the non-linear effects. The advantage of the more simple formulations is, of course, shorter computing time. They find that time-dependent modelling takes about 100 times longer than velocity-bunching and closer to 300 times longer than quasi-linear modelling to produce results.<
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