Focus Stories

Every month we will focus on a specific theme, featuring a selection of articles which have previously been published in GIM International magazine. By including a mix of older and more recent articles, we will present a complete recap of the subject. Furthermore, we will be bringing you a bi-weekly round-up of ‘Focus Stories’ related to the theme through our newsletter (sign up here). The theme for January 2016 is Positioning.

Focus on: Positioning

Developments in Highly Accurate Immersed Tunnel Positioning

Netherlands-based positioning specialist Geocon was awarded a contract for the immersion of one of the deepest and longest immersed tunnels in the world, in South Korea’s Jinhae Bay. Together with its sister company, Strukton Immersion Projects, the main contractor for the immersion operations, Geocon completed the job within the specified ti... (read more)
Bart-Jan Ruesink, Geocon, The Netherlands

3D Precision Beyond the Horizon

The Gemini Offshore Wind Farm in the North Sea is located 85km north of Groningen, The Netherlands. Van Oord, a leading Dredging and Marine Contractor, started the offshore construction work in January 2015. Gemini consists of two separate areas called ‘ZeeEnergie’ and ‘BuitenGaats’, both with 75 4MW Siemens turbines. Gemini... (read more)

GNSS Improvements for Offshore Applications

Currently, there are four global navigation satellite systems (GNSS) available: GPS, Glonass, Beidou and Galileo. These satellites can be used directly, but accuracy is greatly improved when using orbit, clock and UPD correction signals. Fugro Satellite Positioning operates a worldwide network of more than 100 GNSS reference stations capable of tra... (read more)

Guidelines for GNSS ­Positioning

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 t... (read more)

How to Save Time in Offshore Survey Operations

In many instances, offshore survey work is carried out in connection with the construction of, for example, pipelines. The operational scenario is often a string of events where one task has to be completed before the next can be started. This article outlines the increased capabilities of an offshore survey or construction vessel when a small auto... (read more)
Bo Krogh

INS and DVL for Out-of-Straightness Surveying

The move to deeper water, the proliferation of subsea completions, and the continued drive to lower costs are driving the requirement for more accurate out-of-straightness surveys. Pipelines are being designed to higher tolerances and are carrying warmer products at higher pressure. It is assumed that pipes will expand and move throughout their lif... (read more)
James Titcomb, Marc Girault and Fabien Napolitano, iXBlue, France

Looking Far beyond the Horizon

These are exciting times in the geomatics and hydrographic industry. Innovative solutions are being developed, integration is the main keyword and the big players are acquiring smaller companies that add a new dimension to their portfolio. Europe, Japan and North America are traditional strongholds of geomatics, but several very ambitious companies... (read more)

Subsea Array Planning

The development of deepwater and ultra-deepwater subsea fields is one of the greatest challenges facing the offshore oil and gas industry today. The depths involved present a host of engineering challenges during both the development phase and the life of field maintenance programmes. A critical component of the development and maintenance of subse... (read more)
Sam Hanton, Nautronix (UK; Torsten Strandgaard, Geoline (Denmark)

Technology in Focus: How Does Inertial Navigation Work?

In hydrography, we are used to working underwater where no positions are available from satellite navigation systems. In other professional fields, experience has shown that position updates from satellites may not always be available, or are potentially incorrect: examples are unintentional jamming of the extremely weak GNSS signals and signal ref... (read more)

Underwater Positioning

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 betw... (read more)