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The National Oceanic and Atmospheric Administration National Ocean Service's Center for Operational Oceanographic Products and Services has designed and developed a system enhancement to improve data throughput from real-time, remote ocean current monitoring platforms. Aluminum clamp and payload are affixed to U.S. Coast Guard buoys, measure current profile and transmit directly to endpoint databases...
Design and development of lightweight arrays has been a subject of intense study in recent years. This is largely owing to the successful deployment of autonomous vehicles as operational platforms for many underwater applications. The acoustic sensing capabilities of these platforms can be greatly improved by adding a hydrophone array and towing it behind them. Apart from the conventional ceramic...
The frequency of storm surge impacts in western Alaska are likely to increase due to current warming trends leading to accelerated rates of erosion and further inland extent of marine inundation. This leaves the low-lying coastal communities of western Alaska vulnerable to storm surge hazards, especially because our ability to assess risk is hampered by large gaps in monitoring equipment and minimal...
This work reviews a high-speed, direct modulation underwater optical communication link enabled by a combination of polarization and Orbital Angular Momentum (OAM) multiplexing techniques that results in a data rate of 12 Gbit/s. An efficient technique for combining and sorting multiple OAM modes is presented based on log-polar coordinate transformation diffractive phase only optics.
Marine organisms such as phytoplankton and zooplankton are sensitive to the spatial and temporal patchiness of their ecosystems. Properties such as temperature can greatly influence their movement, growth, and survivability. Current efforts towards patch detection have focused on satellite, seaglider, and CTD data of open ocean hydrodynamics. This project aims to tackle an insufficiently studied area...
In polar region operations, drift sea ice positioning and tracking is useful for both scientific and safety reasons. Modeling ice movements has proven difficult, not least due to the lack of information of currents and winds of high enough resolution. Thus, observations of drift ice is essential to an up-to-date ice-tracking estimate. As an inverse problem, it is possible to extract current and wind...
We propose an imaging sonar-based backtracking method as a navigation strategy for an underwater investigation of AUVs. The purpose of backtracking method is to reduce a drift error caused by the inaccuracy of navigation sensors when an AUV returns to its previous position. The AUV divides the trajectory into several intervals and returns to the previous position while correcting small drift error...
A pressing environmental question facing the ocean is the potential impact of possible deep-sea mining activities. This work presents our initial results in developing an ocean and plume modeling system for the Bismark Sea where deep sea mining operations will probably take place. We employ the MSEAS modeling system to both simulate the ocean and to downscale initial conditions from a global system...
Autonomous swarm control, which is expected to be able to handle multiple unmanned vehicles (UxVs), is an important technology that can be applied to many operations and incorporated in many systems. For operations in real environments, we have to consider severe conditions under which communications between UxVs may be inadequate and the environment changes unexpectedly. In addition to optimality,...
In this paper we introduce a method for increasing the autonomy of multiple autonomous underwater vehicles that are conducting an offshore seismic survey. The proposed method concerns the recovery phase that has been done manually in the past. The objective is when the recovery process starts, all the AUVs should autonomously reach the recovery cage, when several AUVs are stacked into the cage, it...
We propose a swarm control algorithm for unmanned vehicles that adapts to unexpected environments while making the optimal formation. Our proposed algorithm, “autonomous and adaptive control”, is inspired by the control mechanism of living organisms and reconciles adaptability under a complex and changing environment and optimality for the various purposes of the system. In this paper, we apply the...
Based on the current widespread use of underwater vehicles, a special type of underwater glider equipped with energy-saving diamond-structured rotatable wings that can improve the underwater vehicle's lift-drag ratio optimize hydrodynamic performance, and enhance flight quality was studied. With the support of adaptive meshing technology and Fluent's epsilon standard turbulence model, lift and drag...
This work presents the generation, dynamic phase modulation and phase detection of interfering composite optical vortices. This technique demonstrates a new method for encoding information onto an optical beam for potential use in underwater communication as well as sensing applications including object detection and channel characterization.
An automated docking system is presented for an autonomous underwater vehicle utilizing light-field imaging for navigation guidance. This article focuses on three major components of the system: docking position acquisition with light-field imaging, optimal docking trajectory planning, and nonlinear trajectory tracking control. With the camera sensor data of each photographic exposure, depth maps...
Recent progress in synthetic aperture sonar (SAS) technology and processing has led to significant advances in underwater imaging, outperforming previously common approaches in both accuracy and efficiency. There are, however, inherent limitations to current SAS reconstruction methodology. In particular, popular and efficient Fourier domain SAS methods require a 2D interpolation which is often ill...
This paper discusses the use of echosounders with forward-looking capabilities (navigation sonar) as scientific instruments for the acquisition of sensor data useful both for short term and long term measurement of Arctic system parameters and variables for the scientific investigation of environmental change and to create data products useful to many communities. Key to accomplishing these goals...
In order to accurately control the portable AUV, a dynamic modeling method based on computational fluid dynamics (CFD) and a improved Generalized Predictive Control (GPC) method were presented. First, the whole modeling process was described from two aspects: dynamic model derivation and model parameter identification. Second, the validity of the model and modeling method were tested by comparing...
The presence of unexploded ordnance (UXO), also referred to as munitions, in the nearshore environment constitutes a risk for the public. Studies of munitions mobility carried out on the foreshore (swash zone) are scarce requiring further analysis. Investigation of munitions mobility/burial through field experiments requires the use of realistic surrogates. This paper focuses on the development of...
Arctic and subarctic conditions represent some of the most challenging environments to make long-term in situ oceanographic measurements. These areas bring the normal challenges of deep water, turbidity, uncertain bottom types and, in areas such as Cook Inlet, some of the world's largest tidal height changes and tidal currents. This paired with the presence of sea ice, which can be up to tens of meters...
Federal government mapping of the offshore areas of the United States in support of the development of oil and gas resources began in 1954. The first mapping system utilized a network of rectangular blocks defined by State Plane coordinates which was later revised to utilize the Universal Transverse Mercator grid. Creation of offshore boundaries directed by the Submerged Lands Act and Outer Continental...
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