The present invention concerns a method for determining a distance and an inclination angle of a surface, using an electro-acoustic transducer with a diffraction pattern comprising at least a main emission lobe around the emission axis of the transducer and a side emission lobe, comprising steps of (i) emitting an acoustic excitation signal toward said surface with said electro-acoustic transducer being disposed with an orientation angle so that at least a part of the signal emitted in the side lobe is incident on the surface with an incidence angle smaller than the average incidence angle of the signal emitted in the main lobe, (ii) collecting an echo signal scattered back to the electro-acoustic transducer by the surface, (iii) identifying in said echo signal a local maximum corresponding to a round trip time of the side lobe signal, and a local maximum corresponding to a round trip time of the main lobe signal, and (iv) calculating the inclination angle and the distance of the surface by taking into account the angular shift of the local maximum of the main lobe signal relative to the emission axis of the transducer.