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

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

Subsea Positioning Transponders Order

Unique Systems (USA) has taken delivery of a major consignment of Compatt 5 subsea positioning transponders from Sonardyne. The order complements Unique's existing worldwide inventory of Sonardyne acoustic equipment which includes RovNav 5 Long BaseLine transceivers and Ranger Ultra-Short BaseLine systems.     Unique Systems is part of the Unique Group based in Sharjah (UAE), which is a major distributor and rental company for advanced marine and diving equipment. The Compatt 5 equipment will be made available to rent from their additional US office in Houston which opened a year ago to support clients and offshore projects throughout the Gulf... (read more)
2009-07-03 11:21:09

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

Pipe-lay Positioning Support

Offshore survey company UTEC has consolidated its presence in the Middle East completing a significant contract for a major international pipelay contractor. The UAE (Dubai) project involved UTEC supporting the DP pipelay vessel in extremely shallow water providing enhanced USBL methodologies. The company also provided survey support services on two additional DP vessels which provided diver support and remedial services to the pipelay vessel. This is the second year in succession that UTEC has provided support to the contractor in the region. UTEC's Global Sales and Marketing director Trevor Hughes commented: “Based on our prior year’s performance the contractor as... (read more)
2013-01-31 10:19:36

Which Satellite Positioning Systems

The International Marine Contractors Association (IMCA, UK) has published new guidance on the selection of satellite positioning systems, warning that in recent years lower priority has been given to system selection than is wise. This is particularly the case when choosing a dynamic positioning (DP). The guide explains that the use of inappropriate systems has led to delays in project execution, vessel downtime and, in some circumstances, damage to assets. In the introduction to ‘Guidance on the Selection of Satellite Positioning Systems for Offshore Applications' (IMCA S 018) the association explains that the costs incurred during any of these incidents... (read more)
2011-07-08 12:00:00

Indonesian Positioning Contract

Veripos, headquartered in the UK, has been awarded a further contract for supply of precision services to PT Pageo Utama of Jakarta, one of Indonesia's leading independent offshore survey organisations.   The facilities involve supply of continuous positioning services aboard two Saipem construction support vessels, the derrick lay barge, Castoro Otto, and the diving support vessel, Eclipse, engaged on key offshore projects for Carigali-Triton Operating Company in Malaysia-Thailand and Premier Oil for the Indonesian Gajah Baru gas field project. Each vessel is being provided with Veripos's Ultra Precise Point Positioning (PPP) service for decimetre-level accuracies together with Verify QC software... (read more)
2011-07-18 11:28:41

Indian Positioning Contracts

Four of India's leading DP vessel operators in Mumbai have each commissioned Veripos to provide medium to long-term high-precision GNSS positioning products and services for their respective domestic and international offshore operations.     The companies include Greatship India who have commissioned Veripos' Standard positioning service and LID3-G1 hardware on DP vessels, Greatship Amrita, Greatship Anjali, Greatship Dhriti, Greatship Disha, and Greatship Diya while a further four vessels are to be supplied with similar facilities later this year.  The company, which has recently had vessels operational in the Middle East, Mexico and South Africa as well as its domestic market in India, is currently engaged in... (read more)
2009-06-23 03:51:21

Veripos Wins Positioning Contract

UK-based companies NCS Survey and InterMoor have awarded Veripos a new three-year contract for provision of GNSS positioning services. The contract will be in support of their respective activities, particularly in and around the North Sea and Brazilian offshore sectors. Facilities to be supplied include a full range of proprietary satellite positioning capabilities, including the company’s latest Apex2 service utilising Precise Point Positioning (PPP) methods in conjunction with both GPS and Glonass constellations. A range of modular hardware comprising versatile integrated mobile units which can be configured to accommodate a wide range of positioning solutions will also be provided, together with... (read more)
2013-02-26 03:39:23

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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