Browsing by Author "Nielsen, Peter L."
Now showing items 1-16 of 16
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A study of the uncertainty in estimate seabed properties as a result of goeacoustic inversion algorithms
Fallat, Mark; Dosso, Stan E.; Nielsen, Peter L. (NATO. SACLANTCEN, 2003/10)This paper investigates the inherent uncertainty in estimated seabed properties derived from matched-field geoacoustic inversion algorithms. This algorithm-induced uncertainty must be considered when interpreting inversion ... -
Application of real data to sonar detection by neural networks
Nielsen, Peter L. (NATO. SACLANTCEN, 1992/11)This memorandum describes the results of applying an artificial neural network for the detection of target echoes. The present study is a continuation of work conducted in 1989 in which a three-layer artificial neural ... -
Broadband geo-acoustic inversion from sparse data using genetic algorithms: results from the 1997 Geo-Acoustic Inversion Workshop
Siderius, Martin; Gerstoft, Peter; Nielsen, Peter L. (NATO. SACLANTCEN, 1998/03)Matched field acoustic inversion techniques were investigated -
Broadband signal simulation in shallow water
Jensen, Finn B.; Ferla, Carlo M.; Nielsen, Peter L.; Martinelli, Giovanna (NATO. SACLANTCEN, 2002/12)Today's minimum requirements for ocean acoustic models are to be able to simulate broadband signal transmissions in 2D varying environments with an acceptable computational effort. Standard -
Geo-acoustic inversion of the PROSIM'97 experimental data using simplex simulated annealing
Fallat, Mark; Nielsen, Peter L.; Jensen, Finn B. (NATO. SACLANTCEN, 2000/01)In the spring of 1997 SACLANTCEN performed an experiment near the Elba island in the Mediterranean Sea. The PROSIM'97 experiment was designed for the validation of a broadband acoustic propagation model. During the period ... -
Geoacoustic inversion using multipath pulse shape
Prior, Mark K.; Harrison, Chris H.; Nielsen, Peter L. (NURC, 2008/09)Experimental data, measured in a shallow water region of the Mediterranean Sea, are used to show that the variation of received intensity with time is well described by existing expressions [Harrison and Nielsen, J. Acoust. ... -
GLider Acoustics Sensing of Sediments (GLASS): experiments and data analysis
Nielsen, Peter L.; Muzi, Lanfranco; Siderius, Martin; Miller, James H. (CMRE, 2013/12)Seabed characteristics (geoacoustic properties and scattering strength) are critical parameters for sonar performance predictions. However, this bottom information is considered very difficult and expensive to achieve in ... -
Glider-based seabed characterization using natural-made ambient noise
Nielsen, Peter L.; Siderius, Martin; Muzi, Lanfranco (CMRE, 2019/06)Seabed characteristics (geoacoustic properties and scattering strength) are critical parameters for sonar performance predictions. However, this bottom information is considered very difficult and expensive to achieve in ... -
Glider-based seabed characterization using natural-made ambient noise
Nielsen, Peter L.; Siderius, Martin; Muzi, Lanfranco (CMRE, 2019/06)Seabed characteristics (geoacoustic properties and scattering strength) are critical parameters for sonar performance predictions. However, this bottom information is considered very difficult and expensive to achieve in ... -
Mode and PE predictions of propagation in range-dependent environments: SWAM'99 workshop results
Nielsen, Peter L.; Jensen, Finn B. (NATO. SACLANTCEN, 2000/05)Three numerical acoustic models, a coupled normal-mode model (C-SNAP), -
Multipath pulse shape in a refracting environment
Harrison, Chris H.; Nielsen, Peter L. (NURC, 2007/11)Multiple boundary interactions in shallow water propagation introduce a more or less Gaussian angle distribution at a distant receiver. When all paths are added the result is 'mode-stripping', i.e. the steep rays are ... -
Multipath pulse shapes in shallow water: theory and simulation
Harrison, Chris H.; Nielsen, Peter L. (NURC, 2007/04)In shallow water propagation the steeper ray angles are weakened most by boundary losses. Regarding the sound intensity as a continuous function of angle it can be converted into a function of travel time to reveal the ... -
PROSIM broadband normal-mode model: a user's guide
Bini-Verona, Francesco; Nielsen, Peter L.; Jensen, Finn B. (NATO. SACLANTCEN, 2000/02)PROSIM is a layered normal-mode model approach for adiabatic broadband range-dependent sound -
Separability of scattering and reflection parameters in reverberation inversion
Harrison, Chris H.; Nielsen, Peter L. (NURC, 2007/11)A premise of reverberation inversion is that one can separate geoacoustic reflection properties from scattering properties since their effects on reverberation are distinguishable. Some doubt has been cast on this premise ... -
Separability of seabed reflection and scattering properties in reverberation inversion
Harrison, Chris H.; Nielsen, Peter L. (NURC, 2007/02)Separation of scattering properties (Lambert's mu) from reflection properties (the reflection loss angle derivative alpha) presents difficulties in the geoacoustic inversion of long range reverberation in isovelocity ... -
The characterization of a range-dependent environment using towed horizontal array data from the MAPEX 2000 experiment
Fallat, Mark; Nielsen, Peter L.; Siderius, Martin (NATO. SACLANTCEN, 2002/11)The characterization of ocean environments using geoacoustic inversion techniques has received a