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

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 Ren√© 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

Positioning Network Enhancements

Global precise positioning supplier Veripos has extended its multi-source Differential GPS service for Africa with the establishment of new reference station facilities at Dar es Salaam, Tanzania and Chimoio in Mozambique, in East Africa. Meanwhile, in West Africa, new reference facilities have also been sited on the island of Sao Tome in the Gulf of Guinea and Lambarene in Gabon. All the stations have been commissioned in response to increased development of regional oil and gas basins in addition to meeting corresponding growth in mineral exploration and production activities.Part of Veripos' worldwide high-precision GNSS positioning operations on behalf of leading... (read more)
2008-09-09 09:35:16

GeoTag Underwater Positioning Solution

Sercel (France) has launched GeoTag, an acoustic positioning solution for seabed seismic acquisition. GeoTag can be used to accurately position all types of ocean bottom cable (obc), ocean bottom node and transition zone cable systems for seabed seismic surveys in water depths down to 500 metres. The GeoTag solution operates with the smallest acoustic positioning transponder available on the market, according to the supplier. The transponders are attached to the seabed seismic equipment and interrogated by a vessel-based transceiver. GeoTag’s design allows for rapid maintenance such as battery replacement for improved crew efficiency. The transponders can also be stored on... (read more)
2015-10-19 10:28:15

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

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

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

Deepsea Positioning Accuracy

First NEMO Tower for Astrophysical Research
The Italian Istituto Nazionale di Fisica Nucleare (INFN) is developing a large underwater apparatus to investigate new frontiers in astrophysical research. The NEutrino Mediterranean Observatory, NEMO, consists of a 3D-array of optical sensors capable of detecting the primary source of extremely high-energy neutrinos. This article covers underwater positioning techniques: system architecture, technical, advanced and data processing aspects, and preliminary data analysis. The first prototype, NEMO Phase 1, was deployed in December 2006 off the coast of Catania. A set of synchronous acoustic beacons was installed in the sea at a depth of 2,000m to position a large number of optical... (read more)
2007-05-31 12:00:00

Guidelines for GNSS ­Positioning

A joint OGP & IMCA Revision of the 1994 UKOOA Guidelines
The original UKOOA Guidelines for the use of differential GPS in offshore surveying, published in 1994, were widely used within the offshore survey industry. In 2005, the International Oil & Gas Producers Association (OGP) took over the custodianship of the guidelines from Oil & Gas UK (formerly UKOOA). At that time it was recognised that the original guidelines needed updating in order to reflect the rapid technical advances in satellite navigation technology of recent years and to maintain the purpose and relevance of the original guidelines. OGP and the International Marine Contractors Association (IMCA) agreed to work together on the... (read more)
2013-01-18 02:14:13
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