Simulation of ship wakes image by an along-track interferometric SAR

Abstract

A mathematical model that allows simulations of the image of waves in ship wakes by either regular or interferometric airborne Synthetic Aperture Radar (SAR or INSAR) is described. The three-component velocity field induced at the ocean surface by a moving ship serves as the input to the model. The simulations take into account the effect of temporal variations of the wave field in the wake on the INSAR imaging by the velocity bunching mechanism. The model also accounts for the scanning distortion of the image. The developed algorithm allows study of the visibility of the ship wave wake by a regular SAR or by lNSAR for arbitrary imaging parameters, as well as for different ship sizes and ship velocity vectors relative to the platform flight track. Various patterns of ship wake images obtained by numerical simulations are presented.

Modeling and SAR Imaging of the Sea Surface: a Review of the State-of-the-Art with Simulations

“…Since the secant function in (42) is undefined for angles of −π/2 and π/2, in implementation, a range for θ excluding the borders (−π/2, π/2) is used. Other numerical methods for Kelvin wake simulation have been described in various studies [59], [60], [115].…”

Observation of a boat and its wake with a Dual-Beam along-track interferometric sar

“…At the same time, wake features, their degree of persistence or their absence altogether can help in gauging the sea surface conditions. Along-track interferometric SAR (AT-InSAR) that senses radial velocity components on the scene offers additional dimension for wake characterization and study [5,6]. These enhanced capabilities can provide further insights in the hydrodynamics of the wake (by measuring flow and wave speeds) and in principle can contribute to the tasks of estimating ship parameters and sea conditions outlined above.…”

“…While Kelvin arms and their SAR/InSAR imaging mechanisms are understood quite well [2,3,6], interferometric signatures and velocity patterns for other parts of the wake are not as widely reported. We focus our attention on the centerline, or "turbulent" wake.…”

Time-Varying Kelvin Wake Model and Microwave Velocity Observation

“…Microwave radar has been proven to be useful in observing the Kelvin wakes. The feature of Kelvin wakes in SAR images and the electromagnetic scattering characteristics from the Kelvin wakes are widely discussed [1][2][3][4][5][6][7][8][9][10][11][12][13]. Based on the Bragg mechanism of the sea surface, Tunaley et al [1] researched the SAR imaging of ship wakes in L-band and analyzed its validity through a comparison with the Sea SAT SAR imagery.…”

“…Oumansour et al [2] investigated the SAR imaging of ship wakes in an X-and L-band utilizing the small perturbation scattering model. Shemer et al [3] described a mathematical model for imaging the ship wakes with the help of the interferometric SAR (INSAR) technique. Henning et al [4] gave an explanation of the principle of SAR imaging of Kelvin arms and discussed the simulated results with experiments.…”