Method for resolving a group of ships - in particular, a formation of naval vessels - or an assemblage of watercraft, wherein the group of ships or the assemblage of watercraft includes at least two watercraft (301, 303), and the watercraft emit underwater sound waves, the method comprising the following steps: - Receiving the underwater sound waves by means of a sonar antenna during a time measurement series [t 0 - t M-1] with M measurement time points, - Determining the individual spectra for each beam of a beam zone with N beams and for each measurement time point, so that N x M individual spectra are obtained, wherein each individual spectrum has a frequency range (f 0 - f END) with individual frequencies, and each individual frequency has an associated amplitude, characterized in that the method comprises the following steps: - Determining a maximum amplitude (MAX) for each individual frequency over the full beam zone for each measurement time point and correspondingly determining the beam associated with the maximum amplitude, - Determining an overall amplitude based on the determined maximum amplitude for each frequency over the time measurement series and notation of a temporal beam path B(t) corresponding in each case to each overall amplitude and/or each frequency, thereby producing a total spectrum with, in each case, a corresponding temporal beam path B(t), - Determining the K greatest overall amplitudes of the total spectrum or the K overall amplitudes lying above a threshold amplitude, wherein K is less than or equal to the number of individual frequencies, - Determining and selecting characteristic beam paths of the K overall amplitudes, - Producing an analysis spectrum of the overall amplitudes corresponding to the selected beam paths, and - Carrying out a pattern recognition process based upon the produced analysis spectrum, so that one of the watercraft is identified. - Receiving the underwater sound waves by means of a sonar antenna during a time measurement series [t 0 - t M-1] with M measurement time points, - Determining the individual spectra for each beam of a beam zone with N beams and for each measurement time point, so that N x M individual spectra are obtained, wherein each individual spectrum has a frequency range (f 0 - f END) with individual frequencies, and each individual frequency has an associated amplitude, characterized in that the method comprises the following steps: - Determining a maximum amplitude (MAX) for each individual frequency over the full beam zone for each measurement time point and correspondingly determining the beam associated with the maximum amplitude, - Determining an overall amplitude based on the determined maximum amplitude for each frequency over the time measurement series and notation of a temporal beam path B(t) corresponding in each case to each overall amplitude and/or each frequency, thereby producing a total spectrum with, in each case, a corresponding temporal beam path B(t), - Determining the K greatest overall amplitudes of the total spectrum or the K overall amplitudes lying above a threshold amplitude, wherein K is less than or equal to the number of individual frequencies, - Determining and selecting characteristic beam paths of the K overall amplitudes, - Producing an analysis spectrum of the overall amplitudes corresponding to the selected beam paths, and - Carrying out a pattern recognition process based upon the produced analysis spectrum, so that one of the watercraft is identified.