Development and Testing of an A-Sized Rapidly Deployable Navigation and Communication GATEWAY Buoy

A rapidly deployable, intelligent GATEWAY buoy system, capable of both air and sea deployment, has been developed to aid in the navigation and communication of Autonomous Underwater Vehicles (AUVs). The device is based around the A-sized (sonobuoy) standard and is deployable from aircraft, helicopters, ships and submarines using pressure and gravity launch tubes or charge-activated devices. The system consists of Florida Atlantic University (FAU) and Woods Hole Oceanographic Institute (WHOI) acoustic modems, both capable of providing Long Base Line (LBL) positioning, Global Positioning System (GPS) Wide Area Augmentation System (WAAS), and Radio Frequency (RF) communications. It utilizes a combined parachute and anchor, a low drag inflatable buoy, and an intelligent scope-adjusting mooring line spool. The design is based around a “fire-and-forget” methodology which, when the system is turned on and launched, requires no initial knowledge of the operating environment. The interoperable acoustic communication (ACOMMS) system can be operated at ranges up to 3000 meters and can achieve a true data rate of up to 860 bits-per-second using reliable spread-spectrum frequency modulation. The LBL positioning system operates sequentially and does not preclude acoustic communications. Switching between protocols (FAU or WHOI) is achieved through an automated process or is requested via RF commands. The mechanical system is modular and compact. The system is capable of operating in depths between 5 m and 200 m, in conditions up to sea state 3, and in currents up to 1.5 m/s. The mooring is versatile and able to hold in bottom types ranging from mud and sand to broken rock and reef.

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A Design for Water Surface Communication System of Ultra Short Base Line Positioning System

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.756-759.2184 ◽

2013 ◽

Vol 756-759 ◽

pp. 2184-2187

Author(s):

Fu Peng Qiu ◽

Hong Jie Wan ◽

Xue Wei Wang

Keyword(s):

Spread Spectrum ◽

Communication System ◽

Water Surface ◽

Direct Sequence Spread Spectrum ◽

Base Line ◽

Positioning System ◽

Main Function ◽

Underwater Acoustic ◽

Design Idea ◽

Offshore Oil

In order to satisfy the requirement of the underwater acoustic positioning system for offshore oil exploration, a design idea for water surface communication system of ultra short base line (USBL) positioning system. The main function of this design is to achieve high-quality communication with underwater acoustic responders. The hardware adopted JZ4760 and the FPGA of altera as the cores. Gold sequence direct sequence spread-spectrum was used on communication system, while modulation was PSK. An appropriate spread-spectrum synchronization mode was presented for the system. MATLAB-based simulation and experiments show that the system is working reliably.

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Induced Magnetic Field-Based Indoor Positioning System for Underwater Environments

Sensors ◽

10.3390/s21062218 ◽

2021 ◽

Vol 21 (6) ◽

pp. 2218

Author(s):

Sizhen Bian ◽

Peter Hevesi ◽

Leif Christensen ◽

Paul Lukowicz

Keyword(s):

Magnetic Field ◽

Low Cost ◽

Autonomous Underwater Vehicles ◽

Wide Band ◽

Propagation Delay ◽

Positioning System ◽

Indoor Environments ◽

Coverage Area ◽

Underwater Positioning ◽

Similar Accuracy

Autonomous underwater vehicles (AUV) are seen as an emerging technology for maritime exploration but are still restricted by the availability of short range, accurate positioning methods necessary, e.g., when docking remote assets. Typical techniques used for high-accuracy positioning in indoor use case scenarios, such as systems using ultra-wide band radio signals (UWB), cannot be applied for underwater positioning because of the quick absorption of the positioning medium caused by the water. Acoustic and optic solutions for underwater positioning also face known problems, such as the multi-path effects, high propagation delay (acoustics), and environmental dependency. This paper presents an oscillating magnetic field-based indoor and underwater positioning system. Unlike those radio wave-based positioning modalities, the magnetic approach generates a bubble-formed magnetic field that will not be deformed by the environmental variation because of the very similar permeability of water and air. The proposed system achieves an underwater positioning mean accuracy of 13.3 cm in 2D and 19.0 cm in 3D with the multi-lateration positioning method and concludes the potential of the magnetic field-based positioning technique for underwater applications. A similar accuracy was also achieved for various indoor environments that were used to test the influence of cluttered environment and of cross environment. The low cost and power consumption system is scalable for extensive coverage area and could plug-and-play without pre-calibration.

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Performance of Spread Spectrum Communication for Underwater Acoustic Positioning System

2020 IEEE 4th Information Technology, Networking, Electronic and Automation Control Conference (ITNEC) ◽

10.1109/itnec48623.2020.9084973 ◽

2020 ◽

Author(s):

Chengcai Lv ◽

Binjian Shen ◽

Chuan Tian ◽

Xinxin Guo ◽

Meng Xiang-Jian ◽

...

Keyword(s):

Spread Spectrum ◽

Spread Spectrum Communication ◽

Positioning System ◽

Underwater Acoustic ◽

Acoustic Positioning

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A Novel Three-SPR Parallel Platform for Vessel Wave Compensation

Journal of Marine Science and Engineering ◽

10.3390/jmse8121013 ◽

2020 ◽

Vol 8 (12) ◽

pp. 1013

Author(s):

Yong Zhan ◽

Huichun Tian ◽

Jianan Xu ◽

Shaofei Wu ◽

Junsheng Fu

Keyword(s):

Compensation Effect ◽

Kinematic Model ◽

Inverse Kinematic ◽

Ship Motion ◽

Forward Kinematics ◽

Positioning System ◽

Sea State ◽

Dynamic Positioning System ◽

Upper Deck ◽

Parallel Platform

A wave compensation platform based on 3-SPR parallel platform is designed for marine ships with a dynamic positioning system. It can compensate for the heave, rolling, and pitching movement of a vessel under level 4 sea state. The forward kinematics of the mechanism is used to draw the central point position workspace and the attitude workspace of the moving deck of the compensation platform. The compensation effects of the 3-RPS parallel compensation platform and the 3-SPR parallel compensation platform are compared, and the feasibility and superiority of the compensation scheme using the 3-SPR parallel compensation platform are proved. To lower the working height of the upper deck of the compensation platform and reduce the extension range of the support legs, the structure of the compensation platform is optimized, and a novel 3-SPR parallel platform is designed. Finally, a simulation model was established. Using the inverse kinematic model as a compensation movement solver which can online calculate the length of branch legs based on the measured heaving, rolling, and pitching values of vessels, the compensation effect of the new structure under a certain sea state is simulated. The result demonstrated the efficiency of the ship motion decoupling movement of the newly designed compensation platform and proved the competence of it.

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Current Effects on a Moored Floating Platform in a Sea State

Volume 4: Ocean Engineering; Offshore Renewable Energy ◽

10.1115/omae2008-57621 ◽

2008 ◽

Cited By ~ 4

Author(s):

Carl Trygve Stansberg

Keyword(s):

Irregular Waves ◽

Mooring Line ◽

Viscous Effects ◽

Floating Platform ◽

Sea State ◽

Scaled Model ◽

Wave Drift ◽

Wave Basin ◽

Wave Drift Damping ◽

Non Gaussian

The significance of current-induced forces and effects on a moored semisubmersible production platform in various sea state conditions is explored, with emphasis on surge motions. Experimental data from 1:55 scaled model tests in a 50m × 80m wave basin are investigated. A description of the current generation is given first. The current in the actual basin is modelled by use of a return current under a false bottom. The importance of modelling a “real” physical current for the proper reproduction of platform responses is pointed out. The semisubmersible tests are carried out with the platform in current only, in irregular waves only, and in combined waves and current conditions. The effects from the current on platform motions and mooring line tensions are investigated. Vortex-Induced motions (VIM) are observed in pure current, depending on the actual combination of current velocity and natural sway period. In combined waves and current the VIM seems to be more or less disappearing. A large effect is seen on the wave drift responses. Both drift forces, non-Gaussian properties and resulting extreme motions and line tensions are significantly increased, especially in high sea states. This is explained through a combination of wave drift damping and viscous effects. At the same time the damping is also increased, but this only partly compensates for the increased forces.

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2A2-L04 Travel Control of an Autonomous Mobile Robot Using an Indoor Positioning System with Spread Spectrum Ultrasonic Waves

The Proceedings of JSME annual Conference on Robotics and Mechatronics (Robomec) ◽

10.1299/jsmermd.2015._2a2-l04_1 ◽

2015 ◽

Vol 2015 (0) ◽

pp. _2A2-L04_1-_2A2-L04_3

Author(s):

Yukiko TAKANO ◽

Taketoshi IYOTA ◽

Kazuhiro WATANABE

Keyword(s):

Mobile Robot ◽

Spread Spectrum ◽

Indoor Positioning ◽

Ultrasonic Waves ◽

Positioning System ◽

Autonomous Mobile Robot ◽

Indoor Positioning System

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Delay-Range-DependentH∞Control for Automatic Mooring Positioning System with Time-Varying Input Delay

Shock and Vibration ◽

10.1155/2014/123107 ◽

2014 ◽

Vol 2014 ◽

pp. 1-11

Author(s):

Xiaoyu Su ◽

Hongzhang Jin ◽

Wei Shen ◽

Yunbiao Gu

Keyword(s):

Sufficient Conditions ◽

Input Delay ◽

Mooring Line ◽

Positioning System ◽

Time Varying ◽

Input Constraint ◽

Mooring Lines ◽

Switching Strategy ◽

Control Forces ◽

Line Switching

Aiming at the economy and security of the positioning system in semi-submersible platform, the paper presents a new scheme based on the mooring line switching strategy. Considering the input delay in switching process,H∞control with time-varying input delay is designed to calculate the control forces to resist disturbing forces. In order to reduce the conservativeness, the information of the lower bound of delay is taken into account, and a Lyapunov function which contains the range of delay is constructed. Besides, the input constraint is considered to avoid breakage of mooring lines. The sufficient conditions for delay-range-dependent stabilization are derived in terms of LMI, and the controller is also obtained. The effectiveness of the proposed approach is illustrated by a realistic design example.

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Feasibility Stage Assessment of Side-By-Side LNG Offloading Operation

Volume 1: Offshore Technology; Special Symposium on Ocean Measurements and Their Influence on Design ◽

10.1115/omae2007-29522 ◽

2007 ◽

Cited By ~ 1

Author(s):

Jun Wong ◽

Colin Paton ◽

Cedric Morandini ◽

Timothy Withall ◽

Andrew Kilner

Keyword(s):

Numerical Simulation ◽

Time Domain ◽

Model Testing ◽

Environmental Data ◽

Mooring Line ◽

High Fidelity ◽

Sea State ◽

Mooring Lines ◽

Starting Point ◽

Relative Motions

A key driver in assessing the economic viability of floating LNG terminals is the marine offloading operations uptime. Marine offloading operations uptime is the percentage of time on site for which weather conditions are such as to permit offloading operations to be undertaken. Physical model testing or time domain numerical simulation techniques can model these marine offloading operations to a very high level of fidelity. However it is not practical for reasons of time and cost to apply such high fidelity modeling to the long duration data sets necessary to make reliable uptime estimates. Simpler solution methods, which can be used to carry out rapid what if studies as well as provide uptime assessment based on very long data records are therefore required. This paper illustrates that a reliable and fast numerical approach based on frequency domain analysis can be developed and used as a pre-screening tool to identify key marine operations uptime drivers. In this method the process of determining the marine offloading operations uptime involves the following steps: 1. Collect and collate site-specific environmental data. The typical starting point for an uptime analysis will be 5 to 10 years of hindcast environmental data, consisting of records of the average wind, wave and current amplitude over successive 3-hour sea states. 2. Evaluate the expected vessel heading in each successive 3-hour sea state throughout the hindcast record. 3. For each 3-hour sea state, estimate the relative motions between the FPSO and LNGC, at the previously determined vessel heading. From the relative motions estimate the envelope of motions of the loading arms and the maximum tensions in the mooring lines between the FPSO and LNGC. 4. For each 3-hour sea state compare the estimated loading arm motion envelopes and maximum mooring line tensions with the maximum acceptable design values to determine whether offloading would be feasible in this 3-hour sea state. 5. Identify times when there are sufficient consecutive 3-hour sea states to allow the offloading operation to be completed (weather window). Determine the percentage uptime from the ratio of the total of these periods to the total environmental data length. A range of sensitivity analysis can also be performed using this methodology, thereby allowing critical cases to be identified for further examination using the high fidelity model testing or time domain numerical simulation programs.

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Application of the Contour Line Method for Estimating Extreme Response in Mooring Lines of a Two-Body Floating Wave Energy Converter

Volume 4: Offshore Geotechnics; Ronald W. Yeung Honoring Symposium on Offshore and Ship Hydrodynamics ◽

10.1115/omae2012-83370 ◽

2012 ◽

Author(s):

Made Jaya Muliawan ◽

Zhen Gao ◽

Torgeir Moan

Keyword(s):

Oil And Gas ◽

Oil And Gas Industry ◽

Contour Line ◽

Mooring Line ◽

Sea State ◽

Gas Industry ◽

Line Method ◽

Extreme Response ◽

Two Bodies ◽

Term Response

One of design criteria that have been used for the mooring system design for floating platforms in the oil and gas industry is the Ultimate Limit State (ULS). The 100-year level response in the mooring line should be applied for this ULS design check, which is ideally estimated by taking into account the dynamic mooring line tension in all sea state available in the operational site. This is called a full long-term response analysis using the all sea state approach. However, this approach is time consuming. Therefore, it is proposed to use the contour line method to estimate the 100-year response by primarily studying the short term response for the most unfavorable sea states along the 100-year environmental contour line. Experiences in the oil and gas industry confirmed that the method could give good prediction if the response at higher percentile than the median is used. In this paper, the mooring system of a two-body wave energy converter (WEC) is considered. Since this system involves interaction between two bodies, the estimation of the ULS level response by using the all sea state approach will be even more time consuming. Therefore, the application of the contour line method for this case will certainly be beneficial. However, its feasibility for a WEC case needs to be documented first. In the present paper, the ULS level response in the mooring tension that is predicted by the contour line method is compared with that estimated by taking into account all sea states. It is achieved by performing the coupled time domain mooring analyses using SIMO/Riflex for six cases with different mooring configurations and connections between two bodies. An axi-symmetric Wavebob-type WEC is chosen as the object of investigation and the Yeu site in France is assumed to be the operational site of the WEC. Hydrodynamic loads including 2nd order forces are determined using WAMIT. Finally, the applicability of the contour line method to predict the ULS level mooring tension for a two-body WEC is assessed and shown to yield accurate results with proper choice of percentile level for the extreme response.

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