The Infona portal uses cookies, i.e. strings of text saved by a browser on the user's device. The portal can access those files and use them to remember the user's data, such as their chosen settings (screen view, interface language, etc.), or their login data. By using the Infona portal the user accepts automatic saving and using this information for portal operation purposes. More information on the subject can be found in the Privacy Policy and Terms of Service. By closing this window the user confirms that they have read the information on cookie usage, and they accept the privacy policy and the way cookies are used by the portal. You can change the cookie settings in your browser.
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...
Military diving operations are routinely conducted in what can be one of the most inhospitable environments on the planet, frequently characterized by zero visibility. The inability to clearly see the immediate operational environment has historically been a serious limitation to manned diving operations — whether the mission is ship husbandry, underwater construction, salvage, or scientific research...
Canada's Exclusive Economic Zone in the Northeast Pacific encompasses a rich variety of offshore benthic habitats, from continental shelf, slope and abyssal sediments, to sponge reefs, seamounts, gas hydrates and hydrothermal vents. Knowledge of these remote areas is uneven, derived from mostly uncoordinated surveys and sampling expeditions by surface vessels, exploration with remotely operated vehicles...
The statistics of extreme wave heights is of great importance in many ocean and coastal engineering applications and is an important part of physical oceanography. For example, in the design and operation of marine structures one needs to take the influence of extreme ocean environments into account and estimates of very large return values of wave heights are often needed. However, due to the limited...
This paper develops a distributed sensor scheduling methodology that utilizes target classification decisions to govern the number of active sensors selected around the target in the deployment region. This approach utilizes a distributed supervisor on each sensor node to control the multi-modal operating state of the node. A distributed sensor selection method is proposed that dynamically adjusts...
The Office of Technology, Planning, and Integration for Observation (TPIO) maintains gap analysis tools that are used to compare both observing system attributes and the National Oceanic and Atmospheric Administration (NOAA) User Observation Requirements to help answer NOAA-wide business questions regarding observational needs and investment. Using the information connected to NOAA products, a capabilities...
During the last years, the underwater inspection of industrial assets, archaeological shipwrecks or geological/biological structures has become an area of interest. Nowadays, these inspections are done by divers or remotely operated vehicles (ROVs). This paper presents a preliminary solution for planning automatic underwater inspections for an autonomous underwater vehicle (AUV) assuming an a priori...
The expanding use of armed, unmanned systems is not only changing the face of modern warfare, but is also altering the process of decision-making in combat operations. These systems have been used extensively in the conflicts in Iraq and Afghanistan, and will continue to be equally relevant — if not more so — as the United States' strategic focus shifts towards the Asia-Pacific region and the high-end...
It is required that in-situ pressure of hydrothermal fluids should be maintained before analyzing. For this reason, gas-tight samplers with accumulator attached on the sample chamber have been developed. Pre-charged gas in the accumulator is used for compensating decompression of sample caused by its volume change during withdrawing onboard. Besides the structure of the sampler, pre-charged internal...
Deep-sea hydraulic system has a high demand for the quality of hydraulic oil. Vacuum filtration and heating operation can effectively remove the water and air bubbles in the mixed oil. A multifunctional oil equipment is proposed in this paper, which possesses both oil filtering and filling functions by vacuum-heating filtering and vacuum-high pressure oiling methods. Finally, the purification effect...
Set the date range to filter the displayed results. You can set a starting date, ending date or both. You can enter the dates manually or choose them from the calendar.