Ship Wake Detectability in TerraSAR X Imagery – Summary and Applications for Wake Detection

Kurzfassung

Ship wakes are produced by the interaction of the ship’s hull with the ocean water and are result of multiple interacting wave systems closely beneath and on the ocean surface. The ship wake signatures in SAR imagery consists of various components. The most frequently encountered wake components are Kelvin wake arms, V-narrow wake arms and two parts of the turbulent wake: the near field and the far field. The detectability of these four most important wake components in SAR imagery is influenced by several physical variables, which are in the following called influencing parameters. The influencing parameters can be categorized into ship properties, environmental conditions and SAR acquisition settings. In a series of preceding studies of the authors, the characteristics of the effects of influencing parameters on the detectability of individual wake components have been modelled using machine learning, categorized, and contrasted against the published state-of-the-art. For the latest study of the authors, the list of the satellites was extended and the detectability of wake components was investigated in terms of different radar frequency bands (C-Band and X-Band SAR) and different orbit altitudes (i.e. slant ranges). This study summarizes the method and the results of the preceding studies and the application of the results to the actual task of wake detection is demonstrated. The demonstration shows that the developed models can be applied to control the precision performance of wake detectors and to estimate vessel velocity with an accuracy coinciding with other published methods.