Ship detection using GNSS-Reflectometry in backscattering configuration

The chance of exploiting the Global Navigation Satellite Systems-Reflectometry (GNSS-R) remote sensing technology in the field of maritime surveillance and ship traffic monitoring has been explored in the very recent past. The conventional bistatic GNSS-R is based on the acquisition of GNSS navigation messages in a forward-scattering geometry, where the investigated region surrounds the specular reflection point. The peculiarities of the ship detection problem, where man-made dihedral structures come into play, make the conventional configuration unsuitable for such an application, especially from spaceborne platforms. Very recently, the backscattering configuration has been demonstrated to greatly enhance the presence of targets within GNSS-R delay-Doppler maps (DDM). In this paper, a thorough comparison of the forward- and back-scattering configurations for ship detection application from spaceborne GNSS-R instruments is presented in order to quantitatively evaluate the benefits of the backscattering configuration with respect to the conventional one. The analysis is performed by computing the signal-to-noise-plus-clutter ratio in both configurations as a function of the sea state, ship orientation and radar look angle.