Browsing by Author "Schmidt, Henrik"
Now showing items 1-16 of 16
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A fast field model for three-dimensional wave propagation in stratified environments based on the global matrix method
Schmidt, Henrik; Glattetre, John (NATO. SACLANTCEN, 1986/03)A three-dimensional fast field program (FFP) model based on the global matrix method will be presented. Compared to traditional propagator matrix methods, the global matrix method allows for a more efficient, and, furthermore, ... -
Benchmarking of SCARAB volume scattering versus OASES volume scattering
Bratberg, Ivar; LePage, Kevin D.; Holland, Charles W.; Schmidt, Henrik (NATO. SACLANTCEN, 2001/05)OASES uses wavenumber integration to solve for the backscattered pressure caused by sound speed and density inhomogeneity scatterers in the sediment; SCARAB uses a ray path technique to find the backscattered intensity. ... -
Efficient global matrix approach to the computation of synthetic seismograms
Schmidt, Henrik; Tango, Gerard (NATO. SACLANTCEN, 1986/05)A numerically efficient global matrix approach to the solution of the wave equation in horizontally stratified environments is presented. The field in each layer is expressed as a superposition of the field produced by the ... -
Evaluation of experimental techniques for determining the plane wave reflection coefficient at the sea floor
Schmidt, Henrik; Jensen, Finn B. (NATO. SACLANTCEN, 1986/06)One of the most commonly used techniques for determinati on of the geoacoustical properties of the sea bed is the measurement of plane wave reflection coefficients at the ocean bottom. An incident field is pr oduced by ... -
Generic Oceanographic Array Technologies (GOATS)'98: bi-static seabed scattering measurements using autonomous underwater vehicles
Schmidt, Henrik; Maguer, Alain; Bovio, Edoardo; Fox, Warren L. J.; LePage, Kevin D.; Pace, Nicholas G.; Hollett, Reginald D.; Guerrini, Piero; Sletner, Per Arne; Michelozzi, Enzo; Moran, B.; Grieve, R. (NATO. SACLANTCEN, 1998/10)The GOATS'98 experiment was performed May 5-29, 1998 in shallow water off Marciana Marina, on the island of Elba, Italy. The experiment addressed some of the fundamental issues associated with using the new Autonomous Ocean ... -
Measurements of acoustic scattering from partially and completely buried spherical shells
Tesei, Alessandra; Maguer, Alain; Fox, Warren L. J.; Schmidt, Henrik (NATO. SACLANTCEN, 1999/04)Recent work at NATO SACLANT Undersea Research Centre has concentrated on investigating the use of low frequency sonars (2-20 kHz) in order to better exploit scattering features of buried targets that can contribute to their ... -
Mechanisms for subcritical penetration into a sandy bottom: experimental and modelling results
Maguer, Alain; Bovio, Edoardo; Fox, Warren L. J.; Pouliquen, Eric; Schmidt, Henrik (NATO. SACLANTCEN, 1998/05)This paper presents the results of a recent study whose overall objectives are to determine the mechanism(s) contributing to subcritical acoustic penetration into ocean sediments, and to quantify the results for use in ... -
Multistatic bottom reverberation in shallow water
Schmidt, Henrik; Lee, Jaiyong; Fan, Huaiyu; LePage, Kevin D. (NATO. SACLANTCEN, 1997)A wavenumber integration approach to modeling of the full multistatic reverberant field produced by small-scale bottom roughness in stratified shallow water waveguides has been developed. A perturbation approach to rough ... -
Physics of 3-D scattering from rippled seabeds and buried targets in shallow water
Schmidt, Henrik (NATO. SACLANTCEN, 1998/05)The new OASES-3D code developed at MIT is used to investigate the spatial and temporal characteristics of reverberation from rippled seabeds insonified by narrow beam sonars such as the TOPAS parametric source. It is shown ... -
Review of numerical models in underwater acoustics including recently developed fast-field program
Jensen, Finn B.; Schmidt, Henrik (NATO. SACLANTCEN, 1984/12)Two papers given by SACLANTCEN personnel at the NATO Advanced Research Workshop on Hybrid Formulation of Wave Propagation and Scattering at Castel Gandolfo, Rome, Italy on 30 August to 3 September 1983 are published as a ... -
SAFARI Seismo-Acoustic Fast field Algorithm for Range-Independent environments: user's guide
Schmidt, Henrik (NATO. SACLANTCEN, 1988/09)An efficient algorithm has been developed for solving the depth-separated wave equation in general fluid/solid horizontlly stratified media. The algorithm has been built into a general-purpose package of computer codes ... -
Shear properties of ocean sediments determined from numerical modelling of Scholte wave data
Jensen, Finn B.; Schmidt, Henrik (NATO. SACLANTCEN, 1986/06)Recently it has become apparent that shear properties of ocean sediments are most easily determined from measured propagation characteristics of seismic interface waves. We use a newly developed numeri ca l model of wave ... -
Spectral integral representations of monostatic backscattering from three dimensional distributions of sediment volume inhomogeneities
LePage, Kevin D.; Schmidt, Henrik (NATO. SACLANTCEN, 2001/03)A theory is developed for generating short time, monostatic reverberation realizations caused by three dimensionally distributed volume inhomogeneities in stratified media. A spectral integral approach to treating the ... -
Spectral integral representations of scattering from volume inhomogeneities
LePage, Kevin D.; Schmidt, Henrik (NATO. SACLANTCEN, 1999/07)In-situ measurements of scattering strength can be obtained by analyzing the early-time, high angle reverberation from bottom and sub-bottom features. In order to provide insight into the mechanisms which cause bottom ... -
Subcritical penetration of narrow Gaussian beams into sediments
Jensen, Finn B.; Schmidt, Henrik (NATO. SACLANTCEN, 1988/03)Complete wave-theory solutions have been obtained numerically for both the reflected and the transmitted fields associated with a narrow Gaussian beam incident on a water-sediment interface near the critical grazing angle. ... -
The use of Love waves to determine the geoacoustic properties of marine sediments
Akal, Tuncay; Schmidt, Henrik; Curzi, P. (NATO. SACLANTCEN, 1986/06)The importance of the geoacoustic properties of marine sediments for low-frequency shallow water propagation is well established. Reliable compressional properties can be obtained from laboratory analysis of collected ...