For many years now, passive observation of the ocean surface, using, in particular, of source of opportunities from positioning satellites (GNSS), has been a very dynamic research and development topic. Several research teams have already demonstrated the relevance of such approaches for airborne observations. The aim of this thesis is to address the feasibility of passive measurements from GPS system signals near the sea surface (a few meters) for recovering oceanographic informations in coastal zones. The sea surface cannot anymore, in this case, be considered as a stationary rough surface. GPS reflected signals must consider the kinematic evolution of the sea surface and the wave motion. The processing of these signals can reveal the temporal variation of the surface, and identify the displacement of the main diffusers (wave crest, buoy on sea surface¿). The motions described here are very slow (some Hz), with respect to the incident wave frequencies (some GHz). The movement amplitude is limited, which induces very short time delay differences. However, despite this difficult context, we have implemented adaptive signal processing techniques, highlighting the detection of movements from the reflected signals. More precisely, our study relies mainly on Kalman filtering in the Doppler-delay space of diffracted signals.
