Underwater Positioning

Centimetric Accuracy Underwater-GPS
By Camille Béchaz, ACSA and Fran­­çois Boucquaert, Fugro-Topnav, France Fugro evaluated the accuracy of the GPS Intelligent Buoy (GIB-Lite) system for its possible use in shallow-water offshore underwater positioning applications. The trials proved that system accuracy could be brought up to centimetre level, the distance between two simultaneously tracked acoustic pingers having a standard deviation of 8cm. Additional works next to an offshore production platform are often required to increase oil recovery from an existing reservoir or to maintain its production rate over a longer period of time. The seabed near such a production platform typically shows pipelines, electric cables,... (read more)
2008-01-01 01:00:00

Satellite Positioning

Within the last twenty years Global Positioning System (GPS) receivers have revolutionised navigation. Integrated devices are capable of providing time, position, height, direction, heave and attitude to accuracies of a few nanoseconds time, 1cm position or 0.01 degree heading. All potentially displayed on a digital chart background with radar and auto-identification system overlays. In this first of two articles we look at current Satellite Positioning systems, how they work and how we can make them better. In a second article, to appear next month, we explore the future development of Satellite Positioning and the implications for navigation. How does Satellite... (read more)
2008-01-01 01:00:00 Kevin Dixon, GNSS Product Manager, NavCom Technology Inc., USA

European Precise Positioning

Ground-based Regional GNSS Augmentation
Global Navigation Satellite Systems (GNSS) like GPS, GLONASS and, soon, Galileo are used for many positioning and navigation applications. But existing GNSS accuracy and reliability do not satisfy all clients. Ground-based augmentation systems provide GNSS observation data and real-time corrections for high-precision positioning and navigation. EUPOS is an initiative to build and run such systems with uniform standards and full-scale accuracy in fifteen Central and Eastern European countries. The European Position Determination System (EUPOS) is both an international initiative and a project to establish a uniform Differential GNSS basis infrastructure in Central and Eastern Europe (CEE). Uniform ground-based multifunctional DGNSS... (read more)
2008-01-01 01:00:00 Anette Blaser and Gerd Rosenthal, Senate Department for Urban Development, Berlin, Germany, Inter

Trident Offshore Positioning Contract

Trident Offshore have commissioned Veripos to provide a full range of precision GNSS positioning services and associated support under an exclusive five-year global contract. The agreement calls for Veripos to provide its complete range of proprietary satellite positioning services extending from its Standard GNSS augmentation service to its Ultra decimetre-accuracy Precise Point Positioning (PPP) capability.   Additionally, Veripos will also provide its range of LD2 and LD3 integrated GNSS receiver and demodulator mobile units together with user-configurable Verify-QC software packages for real-time assessment and post-processing of data as well as support of both single and multi-reference station calculations.     (read more)
2008-03-27 08:46:25

Veripos Americas Positioning Contracts

Veripos' Houston-based Americas Region has been awarded major offshore positioning contracts by DOF Subsea, LSP, Tidewater and WesternGeco for vessels operating in Brazilian, Mexican and US waters. The contracts also cover supply of proprietary integrated demodulator and GNSS receivers and associated software modules to ensure seamless high-precision sub-metre positioning for survey, construction support, seismic and general offshore operations.   Facilities being provided to LSP for its well-testing vessel, Aires Swan, operating in Mexican waters on long-term contract to PEMEX include Veripos' dual-beam Standard and Standard HF augmentation data services together with LD2 and LHD2 integrated demodulator and GNSS receivers. Meanwhile,... (read more)
2008-08-05 01:40:52

Further Petrobras Positioning Contract

Veripos, UK, has been awarded a long-term contract by Petrobras, Brazil, for provision of positioning services in support of the Brazilian state-owned company‚Äôs BGL-1 pipeline installation barge operations.     Under the two-year contract, which includes an option for a further two years, Veripos will provide the 122-metre dynamically-positioned barge with continuous choice of its all-purpose Standard, Ultra and Differential Glonass positioning services supported by LD2-G2 mobile receiver equipment and Verify QC software for real-time position and quality control information.   The contract is the second to have recently been awarded to Veripos by Petrobras following an agreement last year... (read more)
2011-04-28 11:51:06

Survey and Positioning Contract

Aberdeen-based DOF Subsea UK has been awarded a contract worth around GBP2 million by Technip to provide survey and positioning services in BP-operated Block 31, offshore Angola. DOF Subsea will be supplying the services onboard the Skandi Bergen (supplied by DOF Subsea under a separate contract) and on board Technip's lay vessel the Deep Blue. It is anticipated that the project will commence in Quarter 3 2010 and will last for approximately 119 days. DOF Subsea provides subsea construction and engineering, IRM, ROV and survey support services to the world's major subsea markets. The company employs over 1,200 highly qualified... (read more)
2010-02-17 04:44:56

LBL Underwater Positioning

Long baseline (LBL) positioning has many applications both commercially and in research, from surveying a ship hull to positioning offshore platforms in deeper waters. The technique consistently provides accuracies in the order of decimetres over large areas, independent of depth. Recent advances include the integration with other acoustic techniques or with inertial navigation systems for greater levels of accuracy. Since navigation by GPS isbased on electromagnetic signals that cannot penetrate water, subsea positioning requires a different approach. As sounds waves travel through the sea they alternately compress and decompress the water molecules; these compressions/decompressions are detected as changes in pressure.... (read more)
2008-01-19 12:00:00 Elaine Rowan (UK)

Geolab Extends Positioning Contract

Veripos has been awarded a further two-year general services contract by Naples-based GeoLab Srl, a turnkey offshore survey and construction support organisation. The contract extends the relationship between the two companies following an earlier three-year agreement. Under the new agreement Veripos will continue to supply its full range of GNSS positioning solutions in support of GeoLab's fleet of dedicated multi-role survey vessels. These operate worldwide on behalf of major offshore construction and telecommunications companies from GeoLab headquarters in Naples, Italy and other operating bases in Abu Dhabi, Houston, and Pointe Noire in the Congo, West Africa. The solutions cover a... (read more)
2011-03-14 11:02:12 KA

Community-sourced Positioning Project

The TeamSurv consortium offers sailors and powered boaters the opportunity to join a community that collects and shares depth information recorded by vessels' existing depth sounder equipment. Depth data, along with the vessel's position, are automatically logged and stored in real time, either by a software utility running on a Windows PC or using a dedicated hardware logging device. At the end of the voyage, the logged data is uploaded to the TeamSurv website. Submitted data are combined and processed, using unique algorithms, by TeamSurv and are corrected for actual or predicted water levels and other factors so as to... (read more)
2010-03-01 11:09:49
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