Maritime Surveillance Using Spaceborne GNSS-Reflectometry: The Role of the Scattering Configuration and Receiving Polarization Channel

Recent studies have analyzed the chance of exploiting Global Navigation Satellite Systems (GNSS)-Reflectometry observables for maritime surveillance and sea target detection. In this paper, we provide a feasibility study of the ship detection problem using spaceborne GNSS-R data. The analysis is performed via the evaluation of the signal-to-noise-plus-clutter-ratio and signal-to-noise-ratio relevant to an isolated ship target in open sea. In particular, we investigated the impact of the GNSS-R acquisition geometry and radar signal polarization. The influence of sea state and ship orientation is assessed as well. The analysis is based on a sound theoretical electromagnetic model of the bistatic radar cross section of the ship target. The analysis clearly shows the benefits of 1) the backscattering configuration with respect to the conventional forward-scattering one and 2) the RHCP receiving channel w.r.t. the conventional LHCP one, used in sea surface analysis. However, the ship orientation and the sea state still play a key role in ship detectability.