Patent ID: 8767509

Claim:
A method for measuring a contour of the ground ( 6 ) by means of a transmitting arrangement ( 20 ) attached to a watercraft ( 2 ) for the targeted emission of sound signals into an underwater area ( 8 ) and by means of a receiving arrangement ( 28 ) attached to said watercraft ( 2 ), having at least two transducers for receiving the sound waves reflected by the profile of the ground ( 6 ) inside the underwater area ( 8 ), from which the transducers each generate a received signal ( 70 ; 72 ), which is sampled, digitised and stored ( 42 ) at predefined sampling times, said method comprising P 1 P 2 P 3 P 4 P N φ N r N successively emitting a sound signal ( 40 ) into the underwater area ( 8 ) by means of the transmitting arrangement ( 20 ), with a plurality of N soundings from predefined positions (P 1 , P 2 , P 3 , P 4 , . . . , P N ) with aspect angles (φ N ) and distances (r N ) from the contour of the ground ( 6 ) that are different from one another and receiving its components ( 42 ) of the N soundings reflected by the contour of the ground ( 6 ) by means of the receiving arrangement ( 28 ), determining for a plurality of the sampling times and for the N soundings from the received signals ( 70 ; 72 ) both a phase difference ( 44 ) and the path differences ( 46 ) of the received sound waves resulting therefrom between two transducers of the receiving arrangement ( 28 ) determining for these sampling times and for the N soundings associated with the path differences, angles of incidence ( 48 ) and respective incidence coordinates derived therefrom ( 50 ), determining, for these sampling times and for the N soundings at the incidence coordinates, a data density in a predefined region containing the respective incidence coordinate ( 56 ), wherein said data density represents a measure of the number of data points collected within this region, selecting, by means of a maximum detector ( 86 ), the particular region in which the data density becomes a maximum and using the incidence coordinate associated with this region ( 60 ) to determine the contour of the ground ( 6 ).