Background Maritime transportation is vital for international trade, and any disruption to this flow can have severe financial and environmental consequences. Ship mines, both old and new, present significant risks as man-made obstacles. The perilous task of minesweeping, historically carried out by humans at great risk, necessitates the development of unmanned vessels. These autonomous solutions aim to effectively address the dangers posed by ship mines while ensuring the safety of human lives. Objectives This thesis aims to explore the potential of next-generation Mine countermeasure vessel (MCMV) and develop a concept for an autonomous or remotely operated vessel capable of effectively clearing sea mines. This thesis is limited to only considering surface vessels for the MCMV, and alternative designs like submersible vehicles are not considered. Furthermore, the study relies on conventional platform technology, potentially limiting the vehicles’ capabilities compared to emerging technologies. Methods The methodology employed in this degree project is centered on the analysis of current trends and technologies in Mine countermeasure (MCM) operations. Three world-leading products in the field are described in depth to then go through a comprehensive evaluation to serve as a foundation for concept development. Results The outcome of this thesis is a catamaran-based concept that incorporates additional functionalities to enhance its adaptability and self-defense capabilities. The concept extends upon the design of an existing product, incorporating new features such as adjustable width and the ability to support forward reconnaissance, as well as contribute to air defense capabilities within the fleet. Conclusions The future of MCM operations is expected to shift towards automated systems, characterized by smaller and more affordable platforms. This technological advancement enables the increased deployment of MCMVs, with their effectiveness being determined by the number of units rather than individual speed. As technological developments in marine environments continue to progress, the significance of ensuring safety and control in these settings becomes of utmost importance. AutonomousMCMVs will play a vital role in addressing these challenges and contribute significantly to the safety and security of marine environments in the future. / Bakgrund Sjötransporter är avgörande för internationell handel, och störningar i detta flöde kanfå allvarliga ekonomiska och miljömässiga konsekvenser. Fartygsminor, både gamlaoch nya, utgör betydande risker. Uppgiften med att röja dessa hinder, har historisktutförd av människor innebärandes stora risker. Detta har drivit på utvecklingen avobemannade fartyg. Dessa autonoma lösningar syftar till att effektivt ta itu medfarorna som fartygsminor utgör samtidigt som de garanterar människors säkerhet. Syfte Detta examensarbete syftar till att utforska potentialen hos nästa generations MCMVoch utveckla ett koncept för ett autonomt eller fjärrstyrt fartyg som effektivt kanröja sjöminor. Antagandet görs att MCMV antingen kommer att vara autonomeller fjärrstyrd, och alternativa konstruktioner som undervattensfordon övervägs inte.Dessutom bygger studien på nyttjande av konventionell plattformsteknik, vilket po-tentiellt begränsar fordonens kapacitet jämfört med framtida tekniker. Metod Metodiken som används i detta examensarbete är centrerad på analys av aktuellatrender och teknologier i MCM-området. Tre världsledande produkter inom områdetbeskrivs ingående för att sedan gå igenom en omfattande utvärdering, resultatet nyt-tjas för att ligga till grund för konceptutvecklingen. Resultat Resultatet är ett katamaranbaserat koncept som innehåller ytterligare funktioner föratt förbättra dess anpassnings- och självförsvarsförmåga. Konceptet utgår från ut-formningen av en befintlig produkt, med nya tillförda funktioner som justerbar breddoch förmågan att aggera som framskjuten spaning, samt bidra till luftförsvarska-paciteten inom flottan. Slutsatser Framtiden för MCM-verksamheten förväntas skifta mot automatiserade system, kän-netecknade av mindre och mer prisvärda plattformar. Denna tekniska utvecklingmöjliggör byggnation av fler MCMV, där effektiviteten snarare bestäms av antaletenheter än fartygens hastighet. När exploateringen i marina miljöer fortsätter, blirbetydelsen av säkerhet och kontroll i dessa miljöer av yttersta vikt. AutonomaMCMV kommer att spela en viktig roll för att hantera dessa utmaningar.

Approved for public release, distribution unlimited / With the unveiling of ForceNet, the Navy's architectural framework for how naval warfare is to be conducted in the information age, much of the technological focus has been placed on Web technology. One of the most promising technologies is Web services. Web services provide for a standard way to move and share data more reliably, securely, and quickly. The capabilities imbedded in Extensible Markup Language (XML) and Simple Object Access Protocol (SOAP) can merge previously disparate systems into one integrated environment. Already proven successful in the administrative realm, wide-area networks such as the Secure Internet Protocol Network (SIPRNET) have become secure and reliable enough to pass data between systems and units to support tactical operations. The Modeling, Virtual Environments and Simulation (MOVES) Institute at the Naval Postgraduate School is currently working to extend these precepts into the modeling and simulation world under the Extensible Modeling and Simulation Framework (XMSF) project. By leveraging existing Web service technology, warfighters at the "tip of the spear" can have access to previously unrealized amounts of tactically-relevant data, analysis, and planning tools. The goal of this thesis is to apply the XMSF and Extensible 3D (X3D) graphics to the field of sonar visualization. Undersea warfare is a complex operation that requires a continuous and detailed analysis of the acoustic environment. Tactical sensor employment without a firm understanding of the complete undersea picture can lead to fatal consequences. The Navy has spent significant resources to develop training systems and tactical decision aids in an effort to integrate training, rehearsal and execution. Unfortunately, many of the high-resolution analysis tools that can provide high-resolution sonar prediction results are not easily accessible to the fleet. By taking advantage of Web services and XMSF technology, warfighters will need only access to the network to be able to pull real-time environmental analysis data from large databases, remotely run sonar prediction models on supercomputers, and view detailed three-dimensional (3D) virtual worlds that visualize the undersea picture.

This thesis describes the beach field-testing of a 2-degree-of-freedom (2-DOF) transverse line Rayleigh wave source for use in a seismo-acoustic SONAR for buried mine detection. The source is composed of six identical modules, each composed of two radial and two vertical inertial mass shakers, all mounted to a common base plate. The vertical and horizontal excitation of each module is independent. Electrically, the six modules are organized into three independent sets of two. The length of the source is 46 inches (1.17m), the width 6 inches (0.15m) and the weight 126 pounds (562N). Field tests were conducted using a 5-cycle, (smooth-)amplitude-modulated transient excitation signal. Based on past and present experience that the Rayleigh wave speed at the beach test site is approximately 90 m/s, a carrier frequency of 100 Hz was employed, producing a Rayleigh wavelength and surface penetration depth of approximately 1 m (approximately equal to the source aperture length), which is appropriate for the intended application. The source radiation directional characteristics were investigated for various relative amplitudes and phases of vertical and horizontal shaker excitation. A null result was obtained, that is, no unambiguous evidence of directivity was observed in any of the experiments conducted using this source. These included measurements wherein the source modules were removed from the common base plate and emplaced on the sand. The reason for this result is unknown, but it is suspected that a good possibility is that the beach sand medium just below its surface, whereupon the present source and receivers were deployed, is not homogeneous enough to support coherent spatial beamforming. Based upon the past success of a 4-element end-fire line array in producing directional Rayleigh wave radiation (10-15 dB front-to-back rejection), it is suggested that, if such a source can be made mobile, it may well be the best source candidate for a seismo-acoustic SONAR for buried mine detection.

Current rates of technological advancement continue to translate into changes on our battlefields. Aerial robots capable of gathering reconnaissance along with unmanned underwater vehicles capable of defusing enemy minefields provide evidence that machines are playing key roles once played by humans within our military. This thesis explores one of the major problems facing both commercial and military UUVs to date. Successfully navigating in unfamiliar environments and maneuvering autonomously to avoid obstacles is a problem that has yet to be fully solved. Using a simulated 2-D ocean environment, the work of this thesis provides results of numerous REMUS simulations that model the vehicle's flight path over selected sea bottoms. Relying on a combination of sliding mode control and feedforward preview control, REMUS is able to locate obstacles such as seawalls using processed forward look sonar images. Once recognized, REMUS maneuvers to avoid the obstacle according to a Gaussian potential function. In summary, the integration of feedforward preview control and sliding mode control results in an obstacle avoidance controller that is not only robust, but also autonomous.

During Mine Warfare (MIW) operations, MIW analysts perform change detection by visually comparing historical sidescan sonar imagery (SSI) collected by a sidescan sonar with recently collected SSI in an attempt to identify objects (which might be explosive mines) placed at sea since the last time the area was surveyed. This dissertation presents a data structure and three algorithms, developed by the author, that are part of an automated change detection and classification (ACDC) system. MIW analysts at the Naval Oceanographic Office, to reduce the amount of time to perform change detection, are currently using ACDC. The dissertation introductory chapter gives background information on change detection, ACDC, and describes how SSI is produced from raw sonar data. Chapter 2 presents the author's Geospatial Bitmap (GB) data structure, which is capable of storing information geographically and is utilized by the three algorithms. This chapter shows that a GB data structure used in a polygon-smoothing algorithm ran between 1.3 – 48.4x faster than a sparse matrix data structure. Chapter 3 describes the GB clustering algorithm, which is the author's repeatable, order-independent method for clustering. Results from tests performed in this chapter show that the time to cluster a set of points is not affected by the distribution or the order of the points. In Chapter 4, the author presents his real-time computer-aided detection (CAD) algorithm that automatically detects mine-like objects on the seafloor in SSI. The author ran his GB-based CAD algorithm on real SSI data, and results of these tests indicate that his real-time CAD algorithm performs comparably to or better than other non-real-time CAD algorithms. The author presents his computer-aided search (CAS) algorithm in Chapter 5. CAS helps MIW analysts locate mine-like features that are geospatially close to previously detected features. A comparison between the CAS and a great circle distance algorithm shows that the CAS performs geospatial searching 1.75x faster on large data sets. Finally, the concluding chapter of this dissertation gives important details on how the completed ACDC system will function, and discusses the author's future research to develop additional algorithms and data structures for ACDC.

The goal of the research was to develop best practices for image signal processing method for InSAS systems for bathymetric height determination. Improvements over existing techniques comes from the fusion of Chirp-Scaling a phase preserving beamforming techniques to form a SAS image, an interferometric Vernier method to unwrap the phase; and confirming the direction of arrival with the MUltiple SIgnal Channel (MUSIC) estimation technique. The fusion of Chirp-Scaling, Vernier, and MUSIC lead to the stability in the bathymetric height measurement, and improvements in resolution. This method is computationally faster, and used less memory then existing techniques.

Scour is the process of sediment erosion around bridge piers and abutments due to natural and man-made hydraulic activities. Excessive scour is a critical problem that is typically handled by enforcing design requirements that make the submerged structures more resilient. The purpose of this research is to demonstrate the feasibilities of the Optical- Based Green Laser Scanner and HydroLite Sonar in a laboratory setting to capture the 3D profile of simulated local scour holes. The Green Laser had successfully reconstructed a 3D point-cloud imaging of scour profiles under both dry and clear water conditions. The derived scour topography after applying water refraction correction was compared with the simulated scour hole, and was within 1% of the design dimensions. The elevations at the top and bottom surfaces of the 6.5-inch scour hole were -46.6 and -53.11 inches from the reference line at the origin (0,0,0) of the laser scanner. The HydroLite Sonar recorded hydrographical survey points of the scour’s interior surface. The survey points were then processed using MATLAB to obtain a 3D mesh triangulation. / Includes bibliography. / Thesis (M.S.)--Florida Atlantic University, 2018. / FAU Electronic Theses and Dissertations Collection

El objetivo de esta tesis consiste en diseñar un sistema de verificación para sónares utilizados en la actividad pesquera, los cuales están conformados por pequeños cristales piezoeléctricos que emiten pulsos acústicos que realizan el proceso de detección del cardumen. Este estudio comprende el diseño tanto de los circuitos como del programa necesario para determinar la frecuencia de estos elementos y mostrar los resultados en la pantalla del computador. La investigación se desarrolló en cuatro capítulos. En el primer capítulo nos centraremos básicamente en el marco problemático de nuestra investigación, los métodos actuales de verificación de sónares y sus complicaciones. En el segundo capítulo se detallará el estado del arte de esta investigación, las principales aplicaciones del sónar en la industria pesquera, los principales fabricantes de equipos marítimos y los conceptos necesarios para comprender el funcionamiento del sónar. En el tercer capítulo se detalla la metodología que se siguió en este estudio, así como también se muestra el diagrama de bloques del sistema de verificación del estado de los sónares que desarrollamos, a partir del cual se elaboró el diseño de los circuitos de las distintas etapas que comprende este sistema. También se presentan los diagramas de flujo del software que lo controla y por último se detalla la relación de componentes a utilizar. Finalmente, en el cuarto capítulo se hace la evaluación del diseño final del sistema, además se describen las condiciones en que se desarrollaron las pruebas preliminares y se muestran los resultados de las simulaciones tanto del software como del hardware y el costo de su implementación. Como conclusión se desarrollará un sistema eficiente para determinar la eficacia del funcionamiento de los sónares, brindando un servicio mucho más rápido y a menor costo, utilizando la tecnología disponible en el mercado. / Tesis

Kelp beds support a vast and diverse ecosystem including marine mammals, fish, invertebrates, other algae and epibiota, yet these kelp beds can be highly ephemeral. Mapping the density and distribution of kelp beds, and assessing change over yearly cycles, are important objectives for coastal oceanography. However, nearshore habitat mapping is challenging, affected by dynamic currents, tides, shallow depths, frequent non-uniform obstacles and often turbid water. Noisy and often incomplete sensor data compound a lack of landmarks available for navigation. The intelligent, position-aware holonomic ROV (iROV) SeaBiscuit was designed specifically for this nearshore habitat mapping application and represents a novel synthesis of techniques and innovative solutions to nearshore habitat mapping. The concept of an iROV combines the benefits of autonomous underwater navigation and mapping while maintaining the flexibility and security of remote high-level control and supervision required for operation in hostile, complex underwater environments. An onboard battery provides an energy buffer for high-powered thrust and security of energy supply. Onboard low-level autonomy provides robust autopilot features, including station-keeping or course-holding in a flow, allowing the operator to direct the survey and supervise mapping data in realtime during acquisition. With the aim of providing high-usability maps on a budget feasible for small-scale field research groups, SeaBiscuit fuses the data from an orthogonal arrangement of a forward-facing multibeam sonar and a complementary 360° scanning sonar with a full navigation suite to explore and map the nearshore environment. Sensor fusion, coupled with the holonomic propulsion system, also allows optimal use of the information available from the limited budget sensor suite. Robust and reliable localisation is achieved even with noisy and incomplete sensor data using a relatively basic Inertial Navigation System and sonar-aided SLAM in the absence of an expensive Doppler velocity log or baseline navigation system. Holonomic motion in the horizontal plane and an axisymmetric hull provide the manoeuvrability required to operate in this complex environment, while allowing 3D maps to be generated in-transit. The navigation algorithms were tested mapping a piling dock and the habitat mapping sensors calibrated using an ‘artificial’ kelp bed of manually dimensioned kelp stipes transplanted to a sheltered but open-water real-world environment. Sea trials demonstrated mapping open ocean kelp beds, identifying clusters of stipes, converting this into a useful measure of biomass and generating a density surface across the kelp bed. This research provides field-proven techniques to improve the nearshore habitat mapping capabilities of underwater vehicles. Future work includes the transition to full-scale kelp bed mapping, and further development of the vehicle and sensor fusion algorithms to improve nearshore navigation.

Thesis. 1975. Sc.D. cn--Massachusetts Institute of Technology. Dept. of Electrical Engineering and Computer Science. / MICROFICHE COPY AVAILABLE IN ARCHIVES AND ENGINEERING. / Vita. / Bibliography: leaves 368-372. / Sc.D.cn