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Title: Measurement of the Doppler shift in forward-scattered waves caused by moderate sea surface motion in shallow waters.
Creator: Beaujean, Pierre-Philippe, Strutt, Guenael T.
Abstract/Description: A study of the impulse response of the acoustic channel in shallow waters is presented with respect to space, time, and frequency shift over a time window of two hours. A broadband chirp (42–54 kHz) and a narrow band sine wave (58 kHz) are transmitted from a static source located at 51 and 166 m from a vertical line receiver array. In 20 m of water with 0.4 m of wave height, an average Doppler shift of 20 Hz is measured at 51 m range, and 10 Hz at 166 m range, due to the sea-surface motion.
Date Issued: 2005-10
PURL: http://purl.flvc.org/fau/fd/FAUIR000001
Format: Citation

Title: MIMO Underwater Acoustic Communications in Ports and Shallow Waters at Very High Frequency.
Creator: Real, Gaultier, Beaujean, Pierre-Philippe, Bouvet, Pierre-Jean
Date Issued: 2013-10-11
PURL: http://purl.flvc.org/fau/flvc_fau_islandoraimporter_10.3390_jsan2040700_1632229234
Format: Citation

Title: High-Frequency Underwater Acoustic Propagation in a Port Modeled as a Three-Dimensional Duct Closed at One End Using the Method of Images.
Creator: Beaujean, Pierre-Philippe J., Staska, Matthew D.
Date Issued: 2012-06-03
PURL: http://purl.flvc.org/fau/flvc_fau_islandoraimporter_10.1155_2012_929174_1632168479
Format: Citation

Title: Motion Compensation of an Ultra Short Baseline Array for the Acoustic Positioning of an Underwater Vehicle for Port Operations.
Creator: Bon, Antoine, Beaujean, Pierre-Philippe, Florida Atlantic University
Abstract/Description: A Motion Compensated (MC) Ultra Short Baseline (USBL) Acoustic Positioning System (APS) operable in shallow water and port environment has been implemented at Florida Atlantic University. Multi-tones signal modulation and log-likelihood maximization enable this APS to operate in volumes of water of less than 10 cubic meters. Standard deviations of the acoustic source elevation and azimuth estimates were computed to be 3 degrees in an 8 cubic meters test tank, and reduce to 0.9 degree in a 2...
Show moreA Motion Compensated (MC) Ultra Short Baseline (USBL) Acoustic Positioning System (APS) operable in shallow water and port environment has been implemented at Florida Atlantic University. Multi-tones signal modulation and log-likelihood maximization enable this APS to operate in volumes of water of less than 10 cubic meters. Standard deviations of the acoustic source elevation and azimuth estimates were computed to be 3 degrees in an 8 cubic meters test tank, and reduce to 0.9 degree in a 2 meters deep marina. The motion compensating system estimates the array position and orientation while merging noisy measurements from a Magnetic, Angular Rate, and Gravity (MARG) sensor and a Differential Global Positioning System (DGPS) using Kalman filters. Experiments show 0.67 and 2.67 degrees of error for the array tilt and heading estimates, and 0.74 meter for the array position estimate.
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Date Issued: 2007
PURL: http://purl.flvc.org/fau/fd/FA00012507
Subject Headings: Underwater navigation, Acoustical engineering, Adaptive signal processing, Underwater acoustic telemetry
Format: Document (PDF)

Title: Sediment classification of the sea floor using the Chirp Sonar and the Biot model.
Creator: Beaujean, Pierre-Philippe, Florida Atlantic University, LeBlanc, Lester R.
Abstract/Description: A new method is proposed to infer the geotechnical properties of the sea floor from its response to the frequency-modulated pulses emitted by the subbottom profiler called Chirp Sonar. The environment is assumed to be a multilayered medium, composed of homogeneous layers, or an inhomogeneous half-space with depth-dependent properties. The acoustic response of the sediment is computed using the Biot-Stoll theory. The Levenberg-Marquardt method is applied to fit the synthetic response to the...
Show moreA new method is proposed to infer the geotechnical properties of the sea floor from its response to the frequency-modulated pulses emitted by the subbottom profiler called Chirp Sonar. The environment is assumed to be a multilayered medium, composed of homogeneous layers, or an inhomogeneous half-space with depth-dependent properties. The acoustic response of the sediment is computed using the Biot-Stoll theory. The Levenberg-Marquardt method is applied to fit the synthetic response to the experimental response of an homogeneous layer overlying the sea floor. The porosity, the permeability, the mean grain diameter, the mass density, the bulk modulus and the shear modulus within this sediment layer can be estimated. A multilayered medium with depth-dependent properties could be applied to this inversion technique in the future.
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Date Issued: 1995
PURL: http://purl.flvc.org/fcla/dt/15208
Subject Headings: Marine sediments--Acoustic properties, Underwater acoustics--Measurement, Ocean bottom, Sonar
Format: Document (PDF)

Title: An investigation of the influence of surface roughness on reflection coefficients measured by a chirp sonar using a laser profiling of the seafloor.
Creator: Hache, Nicolas., Florida Atlantic University, Beaujean, Pierre-Philippe, Schock, Steven G.
Abstract/Description: This research investigates the validity of an acoustic propagation model by comparing theoretical reflection coefficients, function of frequency, to FAU chirp sonar measurements (chirp sub-bottom profiler). An acoustic model has been implemented to estimate the spectrum of energy reflected from sandy sediments in the presence of surface scattering. The surface roughness being the dominant reverberation part, the volume scattering has been neglected in this model. A laser scanning system...
Show moreThis research investigates the validity of an acoustic propagation model by comparing theoretical reflection coefficients, function of frequency, to FAU chirp sonar measurements (chirp sub-bottom profiler). An acoustic model has been implemented to estimate the spectrum of energy reflected from sandy sediments in the presence of surface scattering. The surface roughness being the dominant reverberation part, the volume scattering has been neglected in this model. A laser scanning system involving an image-processing algorithm has been designed to measure the seafloor bottom roughness using 1D Fourier transforms. In the case of anisotropic roughness, an estimation of the sand ripples dominant direction is provided involving 2D Fourier transforms. Measurements of acoustic data using a chirp sonar and estimation of bottom roughness from video data of the scanner over an artificial bottom are provided to compare the reflection coefficients obtained from the data actually measured with those from the acoustical model.
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Date Issued: 2005
PURL: http://purl.flvc.org/fcla/dt/13212
Subject Headings: Underwater acoustics--Measurement, Marine sediments--Acoustic properties, Oceanography, Seawater--Acoustic properties
Format: Document (PDF)

Title: High-Speed High-Frequency Acoustic Communications in Ports and Shallow Water.
Creator: Blue, Patrick Michael, Beaujean, Pierre-Philippe, Florida Atlantic University
Abstract/Description: A detailed study of a novel method for high-speed acoustic communications in ports and shallow water is presented. A series of field experiments, coupled with simulated results using an acoustic channel model have been conducted to outline the optimal modulation schemes for use in the highly reverberant and Doppler dominated shallow water acoustic channel. Field experiments were conducted in the vicinity of the SeaTech marina and the Port Everglades turning basin in water depths of 2 to 15...
Show moreA detailed study of a novel method for high-speed acoustic communications in ports and shallow water is presented. A series of field experiments, coupled with simulated results using an acoustic channel model have been conducted to outline the optimal modulation schemes for use in the highly reverberant and Doppler dominated shallow water acoustic channel. Field experiments were conducted in the vicinity of the SeaTech marina and the Port Everglades turning basin in water depths of 2 to 15 meters and ranges of between 25 and 75 meters. An automated FAU acoustic modem transmitted BPSK and QPSK modulated messages centered at 300 kHz, with a source level of 173 dB re 1pPa and a symbol bandwidth of 25, 50 or 75 kHz. The coded rate varied from 25000 to 150000 bits per second. These high data rates are made possible using a high resolution Decision Feedback Equalizer with an efficient Doppler compensation process. The results of this study demonstrate the ability of such a system to transmit video images in a shallow water environment.
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Date Issued: 2007
PURL: http://purl.flvc.org/fau/fd/FA00012504
Subject Headings: Underwater acoustics, Deep-sea sounding, Seawater--Acoustic properties
Format: Document (PDF)

Title: Estimation of the scattering function of fading channels for acoustic communications in shallow waters.
Creator: Allemand, Vincent., Florida Atlantic University, Beaujean, Pierre-Philippe
Abstract/Description: The measurement of the Scattering function of time-variant fading channels is of strong interest in the field of underwater acoustic communications, as it indicates the limitations of the channel capacity. It also helps reducing the development time of acoustic communication systems and the need for on-site tests using so-called "fading simulators". The Scattering function is interpreted as the expected power received at a given time-delay and frequency shift for a given signal transmitted...
Show moreThe measurement of the Scattering function of time-variant fading channels is of strong interest in the field of underwater acoustic communications, as it indicates the limitations of the channel capacity. It also helps reducing the development time of acoustic communication systems and the need for on-site tests using so-called "fading simulators". The Scattering function is interpreted as the expected power received at a given time-delay and frequency shift for a given signal transmitted through the acoustic channel. It has been estimated using a fourth-moment method developed by Kailath from 18 to 30 kHz, 8-ms broad-band chirps and 20--28 kHz, 28-ms pseudo noise sequences. These signals were transmitted periodically in the shallow coastal waters of South Florida from a static source, and recorded from a 64-channel receiver array located at a distance of 1000 meters. Spatial beamforming has been applied to study the spatial sensitivity of the scattering function.
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Date Issued: 2005
PURL: http://purl.flvc.org/fcla/dt/13230
Subject Headings: Underwater acoustic telemetry, Signal processing--Digital techniques, Underwater acoustics--Mathematical models, Adaptive signal processing
Format: Document (PDF)

Title: A three-dimensional forward-look sonar simulation model.
Creator: Gazagnaire, Julia., Florida Atlantic University, Cuschieri, Joseph M., Beaujean, Pierre-Philippe
Abstract/Description: The aim of this thesis is to develop a simulation tool, The 3-D Forward-Look Sonar Simulation Model (3-D-FLSSM), for the 3-D Forward Look Sonar or equivalent that provides insight to the defining characteristics of the sonar system that affect the image quality and the data processing. The simulator includes a representation of the acoustic environment, which incorporates a flat seafloor and spherical target, both of which are assumed to a have small-scale roughness (much less than the...
Show moreThe aim of this thesis is to develop a simulation tool, The 3-D Forward-Look Sonar Simulation Model (3-D-FLSSM), for the 3-D Forward Look Sonar or equivalent that provides insight to the defining characteristics of the sonar system that affect the image quality and the data processing. The simulator includes a representation of the acoustic environment, which incorporates a flat seafloor and spherical target, both of which are assumed to a have small-scale roughness (much less than the acoustic wavelength) associated with them. The backscatter from the target and the seafloor are calculated using the Rayleigh-Rice approximation implementing Kuo's backscattering cross section. The simulator is capable of modeling targets of various shapes and sizes. The 3-D-FLSSM assumes a plane wave approximation and a constant sound velocity throughout the water column. The final product is a simulation tool with a focus on shallow water littoral acoustics, which can be used to define the sonar hardware and processing software necessary to meet various operational requirements.
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Date Issued: 2003
PURL: http://purl.flvc.org/fcla/dt/13002
Subject Headings: Sonar--Computer simulation, Underwater acoustics, Remote submersibles
Format: Document (PDF)

Title: Influence of the boundaries on the acoustic scattering by a submerged target.
Creator: Charmes, Emmanuel., Florida Atlantic University, Beaujean, Pierre-Philippe, Cuschieri, Joseph M.
Abstract/Description: In shallow water or fluid half-space, the acoustic scattering from a target is significantly different from that of an unbounded medium, due to the multiple reflections occurring between the target and the boundaries. The purpose of this thesis is to investigate the influence of the boundaries on the acoustic scattering of a rigid sphere by means of a superposition method. A minimum number of point sources necessary to accurately model the scattered field is determined in the case of a free...
Show moreIn shallow water or fluid half-space, the acoustic scattering from a target is significantly different from that of an unbounded medium, due to the multiple reflections occurring between the target and the boundaries. The purpose of this thesis is to investigate the influence of the boundaries on the acoustic scattering of a rigid sphere by means of a superposition method. A minimum number of point sources necessary to accurately model the scattered field is determined in the case of a free medium, a fluid half-space and a waveguide. The free field symmetry vanishes due to the presence of boundaries and, at particular frequencies or scatterer depths, a significant change in the magnitude and spatial distribution of the scattered field occur. In an unbounded medium or fluid half space, the superposition method is shown to give similar results to analytical formulations found in the literature, provided enough point sources are used.
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Date Issued: 2005
PURL: http://purl.flvc.org/fcla/dt/13211
Subject Headings: Electromagnetic waves--Scattering, Acoustical engineering, Sound-waves--Measurement, Wave-motion, Theory of
Format: Document (PDF)

Title: Influence of depth-dependent sediment properties on the pressure reflection coefficient at normal incidence using the Biot-Stoll model.
Creator: Joussein, Marianne., Florida Atlantic University, Beaujean, Pierre-Philippe
Abstract/Description: The impact of depth-dependent geophysical parameters on the acoustic pressure reflection coefficient is studied at normal incidence using the Biot-Stoll theory in porous marine sediments. The seabed is modeled as a sediment layer with depth-dependent properties on top of a homogeneous half-space, as originally proposed by Stern. There is no discontinuity in sediment properties between the layer and the half-space. The reflection coefficient is determined by the evaluation of boundary...
Show moreThe impact of depth-dependent geophysical parameters on the acoustic pressure reflection coefficient is studied at normal incidence using the Biot-Stoll theory in porous marine sediments. The seabed is modeled as a sediment layer with depth-dependent properties on top of a homogeneous half-space, as originally proposed by Stern. There is no discontinuity in sediment properties between the layer and the half-space. The reflection coefficient is determined by the evaluation of boundary conditions at the water-sediment layer interface and the sediment layer-half-space interface. Results are obtained for different types of sediment, from medium size sands to silty clay, and different porosity profiles vs. depth.
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Date Issued: 2004
PURL: http://purl.flvc.org/fcla/dt/13168
Subject Headings: Marine sediments--Acoustic properties, Underwater acoustics--Measurement, Sediments (Geology), Environmental geology
Format: Document (PDF)

Title: Time-dependent multipath modeling for underwater acoustic wave propagation in shallow water.
Creator: Boulanger, Florent Jacques., Florida Atlantic University, Beaujean, Pierre-Philippe
Abstract/Description: A novel acoustic wave propagation model has been developed to determine the effects of the ocean variations on the acoustic propagation field, and to determine the signal measured by a receiver at any distance from an omnidirectional source. The model accounts for environmental conditions. First, a stationary estimate of the complex sound attenuation is computed as a function of frequency and location, using the parabolic equation numerical technique. For a given range, the vertical profile...
Show moreA novel acoustic wave propagation model has been developed to determine the effects of the ocean variations on the acoustic propagation field, and to determine the signal measured by a receiver at any distance from an omnidirectional source. The model accounts for environmental conditions. First, a stationary estimate of the complex sound attenuation is computed as a function of frequency and location, using the parabolic equation numerical technique. For a given range, the vertical profile of the attenuation frequency spectrum is decomposed in the wave number domain. A specific Doppler shift is associated with each wave number. The space-frequency attenuation filter obtained is applied to the transmitted signal to create time-frequency selective fading. This model has been used to simulate the performance of the General Purpose Acoustic Modem, which transmits MFSK modulated sequences between 15.6 kHz to 32.1 kHz. The range of operation varies from 1 to 5 km, in 15 meters of water. Experimental data have been collected under sea-state 2 conditions. The model has been successfully validated when compared to experimental data and to the Crepeau model.
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Date Issued: 2003
PURL: http://purl.flvc.org/fcla/dt/12978
Subject Headings: Underwater acoustics--Mathematical models, Sound--Transmission, Ocean waves--Mathematical models
Format: Document (PDF)

Title: Motion-Compensated Acoustic Positioning in Very Shallow Waters Using Spread-Spectrum Signaling and a Tetrahedral Ultrashort Baseline Array.
Creator: Beaujean, Pierre-Philippe J., Bon, Antoine, An, Edgar
Date Issued: 2010-09-01
PURL: http://purl.flvc.org/fau/flvc_fau_islandoraimporter_10.4031_MTSJ.44.5.4_1629744733
Format: Citation

Title: A generalized model for communicating individuality through teleost swim bladder modulation.
Creator: Matthews, Cameron A., Beaujean, Pierre-Philippe J.
Date Issued: 2018-01-01
PURL: http://purl.flvc.org/fau/flvc_fau_islandoraimporter_10.1242_bio.023515_1632231130
Format: Citation

Title: Calibration and Performance Evaluation for a Multiple Overlapping Field of View Serial Laser Imager.
Creator: Rasoletti, Nicholas, Beaujean, Pierre-Philippe, Florida Atlantic University, College of Engineering and Computer Science, Department of Ocean and Mechanical Engineering
Abstract/Description: The Combined Laser and Scan Sonar (CLASS) system is an extended range imaging system, incorporating both high-resolution laser images and high frequency sonar images. Both the laser and sonar images are collected simultaneously during testing to provide dual mode imagery of an underwater target, displaying both a 2D image of the target (laser image) and a 3D overlay of the target (sonar image). The laser component of the system is a Multiple Overlapping Field of view Serial Laser Imager ...
Show moreThe Combined Laser and Scan Sonar (CLASS) system is an extended range imaging system, incorporating both high-resolution laser images and high frequency sonar images. Both the laser and sonar images are collected simultaneously during testing to provide dual mode imagery of an underwater target, displaying both a 2D image of the target (laser image) and a 3D overlay of the target (sonar image). The laser component of the system is a Multiple Overlapping Field of view Serial Laser Imager (MOFSLI), capable of generating high-resolution sub-centimeter 2D images. MOFSLI generates the images by way of a near diffraction-limited 532 [nm] continuous wave (CW) laser beam being scanned over the target. Initial field tests resulted in high-quality images of the ocean floor, but also indicated the need for additional research on MOFSLI. In this thesis, we focus on the calibration of MOFSLI and on the evaluation of the image quality generated by this system, as a function of range, source power, receiver gain and water turbidity. This work was completed in the specialized underwater electrooptics testing facility located in the Ocean Visibility and Optics laboratory at Harbor Branch Oceanographic Institute (HBOI). Laboratory testing revealed the operational limits of the system, which functioned well until just beyond five attenuation lengths, where it becomes contrast limited due attenuation of target signal and the collection of non-image bearing backscattered photons. Testing also revealed the optimal settings of the system at given environmental conditions.
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Date Issued: 2015
PURL: http://purl.flvc.org/fau/fd/FA00004538, http://purl.flvc.org/fau/fd/FA00004538
Subject Headings: Electrooptics, Inertial navigation systems, Lasers -- Measurement -- Evaluation, Light -- Scattering
Format: Document (PDF)

Title: Characterizing the Magnetic Signature of Internal Waves.
Creator: Nieves, Eric, Beaujean, Pierre-Philippe, Florida Atlantic University, College of Engineering and Computer Science, Department of Ocean and Mechanical Engineering
Abstract/Description: This study is performed in tandem with numerous experiments performed by the U.S. Navy to characterize the ocean environment in the South Florida region. The research performed in this study includes signal processing steps for isolating ocean phenomena, such as internal waves, in the magnetic field. Raw magnetometer signals, one on shore and one underwater, are processed and removed of common distortions. They are then run through a series of filtering techniques, including frequency domain...
Show moreThis study is performed in tandem with numerous experiments performed by the U.S. Navy to characterize the ocean environment in the South Florida region. The research performed in this study includes signal processing steps for isolating ocean phenomena, such as internal waves, in the magnetic field. Raw magnetometer signals, one on shore and one underwater, are processed and removed of common distortions. They are then run through a series of filtering techniques, including frequency domain cancellation (FDC). The results of the filtered magnetic residual are compared to similarly processed Acoustic Doppler Current Profiler (ADCP) data to correlate whether a magnetic signature is caused by ocean phenomena.
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Date Issued: 2017
PURL: http://purl.flvc.org/fau/fd/FA00004917, http://purl.flvc.org/fau/fd/FA00004917
Subject Headings: Ocean currents--Measurement., Adaptive signal processing., Wave-motion, Theory of., Wavelets (Mathematics)
Format: Document (PDF)

Title: Combined spatial diversity and time equalization for broadband multiple channel underwater acoustic communications.
Creator: Skoro Kaskarovska, Violeta, Beaujean, Pierre-Philippe, Florida Atlantic University, College of Engineering and Computer Science, Department of Ocean and Mechanical Engineering
Abstract/Description: High data rate acoustic communications become feasible with the use of communication systems that operate at high frequency. The high frequency acoustic transmission in shallow water endures severe distortion as a result of the extensive intersymbol interference and Doppler shift, caused by the time variable multipath nature of the channel. In this research a Single Input Multiple Output (SIMO) acoustic communication system is developed to improve the reliability of the high data rate...
Show moreHigh data rate acoustic communications become feasible with the use of communication systems that operate at high frequency. The high frequency acoustic transmission in shallow water endures severe distortion as a result of the extensive intersymbol interference and Doppler shift, caused by the time variable multipath nature of the channel. In this research a Single Input Multiple Output (SIMO) acoustic communication system is developed to improve the reliability of the high data rate communications at short range in the shallow water acoustic channel. The proposed SIMO communication system operates at very high frequency and combines spatial diversity and decision feedback equalizer in a multilevel adaptive configuration. The first configuration performs selective combining on the equalized signals from multiple receivers and generates quality feedback parameter for the next level of combining.
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Date Issued: 2015
PURL: http://purl.flvc.org/fau/fd/FA00004411, http://purl.flvc.org/fau/fd/FA00004411
Subject Headings: Adaptive signal processing, MIMO systems, Mobile geographic information systems, Signal processing -- Digital techniques, Underwater acoustic telemetry, Underwater acoustics -- Evaluation, Wireless communication systems
Format: Document (PDF)

Title: Acoustic Tonal and Vector Properties of Red Hind Grouper Vocalizationd.
Creator: Matthews, Cameron Anthony, Beaujean, Pierre-Philippe, Florida Atlantic University, College of Engineering and Computer Science, Department of Ocean and Mechanical Engineering
Abstract/Description: Vertebrates are the most prodigious vocalizing animals in existence, and the most diverse methods of acoustic communication among vertebrates can be found in the ocean. Relatively many teleost fish are gifted with the ability to communicate acoustically, and the family of serranidae often performs this as a function of the swim bladder. Epinephelus Guttatus (E. guttatus), or more commonly the red hind grouper, is equipped with a drum shaped swim bladder acting as a monopole under typical...
Show moreVertebrates are the most prodigious vocalizing animals in existence, and the most diverse methods of acoustic communication among vertebrates can be found in the ocean. Relatively many teleost fish are gifted with the ability to communicate acoustically, and the family of serranidae often performs this as a function of the swim bladder. Epinephelus Guttatus (E. guttatus), or more commonly the red hind grouper, is equipped with a drum shaped swim bladder acting as a monopole under typical ocean conditions. This configuration allows for what is understood to be omnidirectional projection of tones approximately centered between 40 and 440 Hz and spanning anywhere from 40 to 200 Hz of bandwidth and modulation effects based on observed data provided by researchers. Prior studies on many other fish show correlation in acoustic communication profile with length, size and sexual identity. In the red hind, sexual dimorphism leads to an inherent female identity in all juvenile fish which converts to male according to environmental factors, recommending at least consistent organs across both sexes be assumed even if not in use. Much research has been performed on male fish vocalization in terms of spectral content. Communication in fish is a complex multi-modal process, with acoustic communication being important for many of the species, particularly those in the littoral regions of the worlds’ oceans. If identifying characteristics of the red hind vocalization can be isolated based on detection, classification, tracking and localizing methodologies, then these identifying characteristics may indeed lead to passive feature identification that allows for estimation of individual fish mass. Hypotheses based on vector, cyclostationary and classical tonal mechanics are presented for consideration. A battery of test data collection events, applying pre-recorded fish vocalizations to a geolocated undersea sound source were conducted. The results are supplied with the intent of validating hypothesis in a non-expert system manner that shows how a series of biological metrics may be assessed for detection, classification, localization and mass estimation for an individual vocalizing red hind grouper
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Date Issued: 2017
PURL: http://purl.flvc.org/fau/fd/FA00004826, http://purl.flvc.org/fau/fd/FA00004826
Subject Headings: Wave-motion, Theory of., Sound production by animals., Fishes--Vocalization., Bioacoustics., Animal communication., Underwater acoustics., Acoustic surface waves.
Format: Document (PDF)

Title: APPLYING BLIND SOURCE SEPARATION TO MAGNETIC ANOMALY DETECTION.
Creator: Nieves, Eric, Beaujean, Pierre-Philippe, Florida Atlantic University, Department of Ocean and Mechanical Engineering, College of Engineering and Computer Science
Abstract/Description: The research shows a novel approach for the Magnetic Anomaly Differentiation and Localization Algorithm, which simultaneously localizes multiple magnetic anomalies with weak total field signatures (tens of nT). In particular, it focuses on the case where there are two homogeneous targets with known magnetic moments. This was done by analyzing the magnetic signals and adapting Independent Component Analysis (ICA) and Simulated Annealing (SA) to solve the problem statement. The results show the...
Show moreThe research shows a novel approach for the Magnetic Anomaly Differentiation and Localization Algorithm, which simultaneously localizes multiple magnetic anomalies with weak total field signatures (tens of nT). In particular, it focuses on the case where there are two homogeneous targets with known magnetic moments. This was done by analyzing the magnetic signals and adapting Independent Component Analysis (ICA) and Simulated Annealing (SA) to solve the problem statement. The results show the groundwork for using a combination of fastICA and SA to give localization errors of 3 meters or less per target in simulation and achieved a 58% success rate. Experimental results experienced additional errors due to the effects of magnetic background, unknown magnetic moments, and navigation error. While one target was localized within 3 meters, only the latest experimental run showed the second target approaching the localization specification. This highlighted the need for higher signal-to-noise ratio and equipment with better navigational accuracy. The data analysis was used to provide recommendations on the needed equipment to minimize observed errors and improve algorithm success.
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Date Issued: 2020
PURL: http://purl.flvc.org/fau/fd/FA00013610
Subject Headings: Magnetic anomalies, Simulated annealing (Mathematics), Independent component analysis, Unmanned vehicles
Format: Document (PDF)

Title: APPLICATION OF SIGNAL DECOMPOSITION TO IMPROVE TIME DELAY ESTIMATES FOR SYNTHETIC APERTURE SONAR MOTION COMPENSATION.
Creator: Gazagnaire, Julia, Beaujean, Pierre-Philippe, Florida Atlantic University, Department of Ocean and Mechanical Engineering, College of Engineering and Computer Science
Abstract/Description: Synthetic Aperture Sonar (SAS) provides the best opportunity for side-looking sonar mounted on underwater platforms to achieve high-resolution images. However, SAS processing requires strict constraints on resolvable platform motion. The most common approach to estimate this motion is to use the Redundant Phase Center (RPC) technique. Here the ping interval is set, such that a portion of the sonar array overlaps as the sensor moves forward. The time delay between the pings received on these...
Show moreSynthetic Aperture Sonar (SAS) provides the best opportunity for side-looking sonar mounted on underwater platforms to achieve high-resolution images. However, SAS processing requires strict constraints on resolvable platform motion. The most common approach to estimate this motion is to use the Redundant Phase Center (RPC) technique. Here the ping interval is set, such that a portion of the sonar array overlaps as the sensor moves forward. The time delay between the pings received on these overlapping elements is estimated using cross-correlation. These time delays are then used to infer the pingto-ping vehicle motion. Given the stochastic nature of the operational environment, some level of decorrelation between these two signals is likely. In this research, two iterative signal decomposition methods well suited for nonlinear and non-stationary signals, are investigated for their potential to improve the Time Delay Estimation (TDE). The first of this type, the Empirical Mode Decomposition (EMD) was introduced by Huang in the seminal paper, The empirical mode decomposition and the Hilbert spectrum for nonlinear and non-stationary time series analysis and is the foundation for the algorithms used in this research. This method decomposes a signal into a finite sequence of simple components termed Intrinsic Mode Functions (IMFs). The Iterative Filter (IF) approach, developed by Lin, Wang and Zhou, builds on the EMD framework. The sonar signals considered in this research are complex baseband signals. Both the IF and EMD algorithms were designed to decompose real signals. However, the IF variant, the Multivariate Fast Iterative Filtering (MFIF) Algorithm, developed by Cicone, and the EMD variant, the Fast and Adaptive Multivariate Empirical Mode Decomposition (FAMVEMD) algorithm, developed by Thirumalaisamy and Ansell, preserve both the magnitude and phase in the decomposition and hence were chosen for this analysis.
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Date Issued: 2021
PURL: http://purl.flvc.org/fau/fd/FA00013795
Subject Headings: Sonar, Signal processing, Synthetic apertures
Format: Document (PDF)

FAU Theses and Dissertations (27)	+ -
FAU College Collections (7)	+ -

Underwater acoustic telemetry (8)	+ -
Adaptive signal processing (7)	+ -
Underwater acoustics--Measurement (5)	+ -
Acoustical engineering (3)	+ -
Marine sediments--Acoustic properties (3)	+ -

Underwater acoustics (3)	+ -
MIMO systems (2)	+ -
Reinforced concrete (2)	+ -
Reinforcing bars--Corrosion (2)	+ -
Remote submersibles (2)	+ -
Seawater--Acoustic properties (2)	+ -
Signal processing (2)	+ -
Signal processing--Digital techniques (2)	+ -
Sonar (2)	+ -
Underwater acoustics -- Evaluation (2)	+ -
Underwater acoustics--Instruments (2)	+ -
Underwater acoustics--Mathematical models (2)	+ -
Underwater navigation (2)	+ -
Wave-motion, Theory of. (2)	+ -
Wireless communication systems (2)	+ -
Acoustic surface waves. (1)	+ -
Acoustics (1)	+ -
Adaptive signal processing. (1)	+ -
Animal communication. (1)	+ -
Artificial satellites in telecommunication (1)	+ -
Autonomous underwater vehicles (1)	+ -
Bioacoustics. (1)	+ -
Computer integrated manufacturing systems (1)	+ -
Deep-sea sounding (1)	+ -
Electromagnetic waves--Scattering (1)	+ -

Electronic Thesis or Dissertation (27)	+ -
article (7)	+ -

Beaujean, Pierre-Philippe (28)	+ -
Florida Atlantic University (27)	+ -
College of Engineering and Computer Science (18)	+ -
Department of Ocean and Mechanical Engineering (17)	+ -
Beaujean, Pierre-Philippe J. (6)	+ -

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