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Polarisation influence on sea clutter properties and radar detection performance in X-band for low grazing angles

This paper establishes a comparison of sea clutter properties and radar detection performance depending on polarisation and conditions of observation. A theoretical approach based on the most common models for sea clutter properties first shows that the polarisation yielding the best performance depends on a precise set of parameters, namely the grazing angle, wind speed and radar height. The models used here concern the reflectivity coefficient, the amplitude statistics, and the spectral behaviour. A detailed statistical analysis of a sea clutter database then confirms the effects of polarisation on the sea clutter properties, and the influence of this set of parameters on the best polarisation in terms of detection performance. The vertical polarisation thus proves to yield much better detection performance for low grazing angles and high sea states, for both coherent and non-coherent detection schemes. The conditions for which both vertical and horizontal polarisations yield the same level of detection performance are also analysed.