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

Malaysian Positioning Contract

Veripos has been awarded a new three-year contract by Kuala Lumpur-based Orogenic Geoexpro for continued provision of GNSS positioning services to the Malaysian company’s fleet of vessels engaged on geophysical surveys, rig moves and major construction support projects throughout Southeast Asia. Services provided by Veripos under the contract include a combination of its dual-beam standard and ultra Precise Point Positioning (PPP) facilities supported by shipborne hardware comprising 30 LD3SG1 and 10 LD3G2 integrated mobile receivers. Also available is a series of proprietary software modules for real-time monitoring, control and QC operations. (read more)
2012-04-26 12:00:00

Indonesian Positioning Contract

Veripos has been awarded a two-year contract by hydrographic survey and subsea specialists PT Pageo Indonesia of Jakarta for provision of high-precision Differential GPS positioning services in support of major site survey and rig-positioning operations being carried out in the Mahakam Delta, Kalimantan on behalf of Total E&P Indonesie, a subsidiary of the Total Group of companies.   The services, which include supply of Veripos' latest LD3 integrated mobile GPS receiver and demodulators for calculating positions and output of data, are being used in support of jackup, semi-submersible and swamp drilling barge operations as well as shallow water survey vessels... (read more)
2008-02-04 03:25:53

Workshop on Underwater Positioning

The Hydrographic Society organised a workshop on underwater positioning and navigation on Wednesday 10th December 2008. On board of the tug René Siegfried, three presentations were held, touching various aspects of the matter.   Hans-Willem de Leeuw (sales engineer, IXSEA Benelux) explained the principle of the fibre optic gyroscope and introduced various applications of this technique in the IXSEA product range. Especially in the offshore, there is a demand for precise underwater navigation and the combination of the fibre-optic gyroscopes with GPS or DVL make the positioning more accurate, even after hours.   Neil MacDonald (technical manager, Applied Acoustics) went... (read more)
2008-12-12 10:30:25

Deepwater Positioning Buoys Shipment

Falmouth Scientific has shipped 30 deepwater positioning buoys worth almost half-a-million US dollars to the Integrated Ocean Drilling Program (IODP). These beacons will be employed by IODP's drilling vessel for deepwater (6000-meter) positioning. FSI's instruments will be used to accurately position IODP's drilling ships in order to extract cores of the Earth's crust at the bottom of the ocean.   The mission of the IODP is to explore Earth's history and structure recorded in seafloor sediments and rocks, and to monitor sub-seafloor environments. Their efforts are part of a global team from the US, Japan, China, Korea and Europe.  ... (read more)
2008-08-14 12:14:15

Survey and Positioning Contract

DOF Subsea UK has entered into a long term agreement with Heerema Marine Contractors Nederland BV (HMC) to provide survey and positioning services onboard its deepwater construction vessels. The agreement covers a worldwide scope, but the current focus is on projects which are already underway in the Gulf of Mexico and West Africa. Commenting on the contract award, Garry Millard, DOF Subsea UK’s Managing Director said, “We’re delighted to be awarded with this agreement. It confirms the trust and commitment that has developed between both companies over the last five years and gives us the opportunity to further demonstrate our... (read more)
2008-10-29 12:04:42

High Precision Positioning

Extension of the Condamine Port in Monaco
The port of Monaco is undergoing an extensive construction process that will help double the port's capacity and protect it from heavy eastern swells and dangerous Mediterranean storms. The new port will include two unusual pontoon-type breakwaters as well as an additional hectare of land reclaimed from the sea. The project, costing more than 243 million euro, was initiated in June 1999 and is today slightly ahead of schedule. The existing port was built at the beginning of the century. At that time the water was too deep to allow, using building techniques of the day, construction of a jetty... (read more)
2008-01-01 01:00:00

OMEX Positioning Contract

Veripos has been awarded a five-year contract by Odyssey Marine Exploration (OMEX) of Tampa, USA, for supply of positioning services aboard its newly-renovated deep-ocean exploration vessel, MV Dorado Discovery. The 98m-long vessel, which is among the world's most advanced of its type, is due to begin an extensive series of mineral exploration and recovery surveys in the South Pacific, working offshore Papua New Guinea and Tonga. Under the contract, Veripos will provide MV Dorado Discovery with a combination of its global Ultra Precise Point Positioning (PPP) service for decimetre-level accuracies together with LD2-G2 integrated mobile receivers; associated software provisions include... (read more)
2010-09-30 11:17:55

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
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