Modeling and theoretical exploration of free surface manifestation of submarines in presence and absence of ocean waves

Maritime surveillance using remote -sensing images is one of the emerging technologies. Because of the inaccessibility of real-time remote -sensing images, it is imperative to model them. The main intention of this study is to investigate the factors influencing the detection of submarines, irrespective of the imaging sensors. In the present work, submarine wakes (Bernoulli hump and Kelvin wake) are modeled and integrated with the sea surface to examine the key features of the submarine. Here, the sea surface is simulated by linear Airy theory using the Elfouhaily spectrum, and novel submarine position projection in imaging coordinate (SPPIC) technique is introduced to generate synthetic free surface wakes in different orientations. Besides, Computational Fluid Dynamics (CFD) technology is utilized to assess and endorse the SPPIC-based simulated wake models. The Beaufort scale is used to validate the modeled sea surface, and the root mean square error of the model is 0.314 m. Then, the simulated submarine wakes are verified by analyzing its essential features and extracting the significant parameters of submarine, such as moving velocity, heading angle, and diving depth. Further, the current research explores these significant characteristics in the context of ocean waves. The Fourier transform technique is employed to retrieve the heading angle and velocity of the submarine. The introduction of variance distribution in the Radon transform method resolves the 180 0 ambiguity problem in heading angle calculation. Additionally, negative exponential relation is established between the diving depth of the submarine and the height of the Bernoulli hump. From this empirical equation, one can fetch the diving depth of the submarine. The discrete wavelet transform approach enhances the edges of the wedge Kelvin wake in the presence of sea waves and is demonstrated with real-time synthetic aperture radar images. Moreover, primary wake features are investigated and evaluated for different classes of submarines.