Image Number 12 for United States Patent #7317660.
A system and method for measuring the directional spectrum of one or more waves in a fluid medium using a multi-beam sonar system is disclosed. In an exemplary embodiment, range cells located within a plurality of acoustic beams are sampled to provide current velocity data. Optionally, wave surface height and pressure data is obtained as well. A sensitivity vector specifically related to the ADCP's transducer array geometry is used in conjunction with maximum likelihood method (MLM), iterative maximum likelihood method (IMLM), or other similar methods to solve a the wave equation at each frequency and produce a frequency-specific wave directional spectrum. The frequency-specific spectra are combined to construct a complete two-dimensional wave directional spectrum.