Abstract: A system and a method for determining one or more wave characteristics from a moving platform are disclosed. A sonar system, such as an Acoustic Doppler Current Profiler, can profile the water motion relative to the platform, and an earth reference can determine a measure of the platform motion relative to a fixed earth reference. Both water profile and earth reference measurements can be synergistically employed to compensate for motion of the platform. Directional wave spectra and non-directional wave spectrum can be computed and translated via linear wave theory to surface height spectra and used to calculate characteristics, such as significant wave height, peak period, and peak direction.

Abstract: Underwater vehicles may fix their position from GPS at the surface of the water and use bottom track for dead reckoning once it has descended to within tracking range of the bottom of a body of water. This disclosure describes a method and system for navigation through the water through depths where GPS is not available using current profiles from sonar systems including acoustic Doppler current profilers (ADCP). This extrapolation of earth referenced current profiles can provide a way to estimate vehicle motion below the surface before the vehicle reaches the bottom. Once bottom track is achieved, the corrected reference for vehicle motion improves the vehicle position estimate. A Kalman filter updates vehicle position and current profile estimates during descent, and the bottom track when the bottom comes within range to enable navigation of underwater vehicles.

Abstract: Underwater vehicles may fix their position from GPS at the surface of the water and use bottom track for dead reckoning once it has descended to within tracking range of the bottom of a body of water. This disclosure describes a method and system for navigation through the water through depths where GPS is not available using current profiles from sonar systems including acoustic Doppler current profilers (ADCP). This extrapolation of earth referenced current profiles can provide a way to estimate vehicle motion below the surface before the vehicle reaches the bottom. Once bottom track is achieved, the corrected reference for vehicle motion improves the vehicle position estimate. A Kalman filter updates vehicle position and current profile estimates during descent, and the bottom track when the bottom comes within range to enable navigation of underwater vehicles.

Abstract: A system and a method for determining one or more wave characteristics from a moving platform are disclosed. A sonar system, such as an Acoustic Doppler Current Profiler, can profile the water motion relative to the platform, and an earth reference can determine a measure of the platform motion relative to a fixed earth reference. Both water profile and earth reference measurements can be synergistically employed to compensate for motion of the platform. Directional wave spectra and non-directional wave spectrum can be computed and translated via linear wave theory to surface height spectra and used to calculate characteristics, such as significant wave height, peak period, and peak direction.

Abstract: A system and a method for determining one or more wave characteristics from a moving platform are disclosed. A sonar system, such as an Acoustic Doppler Current Profiler, can profile the water motion relative to the platform, and an earth reference can determine a measure of the platform motion relative to a fixed earth reference. Both water profile and earth reference measurements can be synergistically employed to compensate for motion of the platform. Directional wave spectra and non-directional wave spectrum can be computed and translated via linear wave theory to surface height spectra and used to calculate characteristics, such as significant wave height, peak period, and peak direction.

Abstract: A system and a method for determining one or more wave characteristics from a moving platform are disclosed. A sonar system, such as an Acoustic Doppler Current Profiler, can profile the water motion relative to the platform, and an earth reference can determine a measure of the platform motion relative to a fixed earth reference. Both water profile and earth reference measurements can be synergistically employed to compensate for motion of the platform. Directional wave spectra and non-directional wave spectrum can be computed and translated via linear wave theory to surface height spectra and used to calculate characteristics, such as significant wave height, peak period, and peak direction.

Abstract: A system and method of horizontal wave measurement is disclosed. The system for measuring the directional spectrum of waves in a fluid medium having a substantially planar surface may include a sonar system having a plurality of transducers for generating respective acoustic beams and receiving echoes from one or more range cells located substantially within the beams, at least one of the plurality of acoustic beams being angled non-orthogonally to at least one other of the plurality of acoustic beams. The method may calculate the directional spectrum associated with the waves from the received echoes.

Abstract: A system and method for measuring the directional spectrum of one or more waves in a fluid medium using a multi-beam sonar system. 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. This velocity, wave height, and pressure data is Fourier-transformed by one or more signal processors within the system, and a surface height spectrum produced. A cross-spectral coefficient matrix at each observed frequency is also generated from this data. 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.

Abstract: A system and method of horizontal wave measurement is disclosed. The system for measuring the directional spectrum of waves in a fluid medium having a substantially planar surface may include a sonar system having a plurality of transducers for generating respective acoustic beams and receiving echoes from one or more range cells located substantially within the beams, at least one of the plurality of acoustic beams being angled non-orthogonally to at least one other of the plurality of acoustic beams. The method may calculate the directional spectrum associated with the waves from the received echoes.

Abstract: A system and method of horizontal wave measurement is disclosed. The system for measuring the directional spectrum of waves in a fluid medium having a substantially planar surface may include a sonar system having a plurality of transducers for generating respective acoustic beams and receiving echoes from one or more range cells located substantially within the beams, at least one of the plurality of acoustic beams being angled non-orthogonally to at least one other of the plurality of acoustic beams. The method may calculate the directional spectrum associated with the waves from the received echoes.

Abstract: 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.

Abstract: A system and method of horizontal wave measurement is disclosed. The system for measuring the directional spectrum of waves in a fluid medium having a substantially planar surface may include a sonar system having a plurality of transducers for generating respective acoustic beams and receiving echoes from one or more range cells located substantially within the beams, at least one of the plurality of acoustic beams being angled non-orthogonally to at least one other of the plurality of acoustic beams. The method may calculate the directional spectrum associated with the waves from the received echoes.

Abstract: A system and method for measuring the directional spectrum of one or more waves in a fluid medium using a multi-beam sonar system. 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. This velocity, wave height, and pressure data is Fourier-transformed by one or more signal processors within the system, and a surface height spectrum produced. A cross-spectral coefficient matrix at each observed frequency is also generated from this data. 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.

Abstract: A system and method for measuring the directional spectrum of one or more waves in a fluid medium using a multi-beam sonar system. 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. This velocity, wave height, and pressure data is Fourier-transformed by one or more signal processors within the system, and a surface height spectrum produced. A cross-spectral coefficient matrix at each observed frequency is also generated from this data. 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.

Abstract: A system and method for measuring the directional spectrum of one or more waves in a fluid medium using a multi-beam sonar system. 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. This velocity, wave height, and pressure data is Fourier-transformed by one or more signal processors within the system, and a surface height spectrum produced. A cross-spectral coefficient matrix at each observed frequency is also generated from this data. A sensitivity vector specifically related to the ADCP's transducer array geometry is used in conjunction with maximum likelihood method (NLM), 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.

Abstract: A system and method for measuring the directional spectrum of one or more waves in a fluid medium using a multi-beam sonar system. 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. This velocity, wave height, and pressure data is Fourier-transformed by one or more signal processors within the system, and a surface height spectrum produced. A cross-spectral coefficient matrix at each observed frequency is also generated from this data. 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.

Abstract: A system and method for measuring the directional spectrum of one or more waves in a fluid medium using a multi-beam sonar system. 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. This velocity, wave height, and pressure data is Fourier-transformed by one or more signal processors within the system, and a surface height spectrum produced. A cross-spectral coefficient matrix at each observed frequency is also generated from this data. 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.