IMCA Newsroom

Press Release 30/05

GUIDANCE ON SHARED USE OF DGPS FOR DP AND SURVEY OPERATIONS

Guidelines for the shared use of DGPS (differential global positioning system) for DP (dynamic positioning) and survey operations have been published by IMCA, the International Marine Contractors Association.

"Differential global navigation satellite systems (DGNSS) such as DGPS and differential GLONASS (DGLONASS) are acknowledged as global standards for precise positioning and navigation and are used extensively within DP systems to guide vessels involved in offshore survey and construction operations," explains Hugh Williams, Chief Executive of IMCA.

"Before this, DP vessels would typically use radio-navigation systems provided and operated by a survey-positioning company. These were normally installed for the duration of a particular contract or project. The survey-positioning company retained full responsibility for the system, which would be used for both survey and DP requirements.

"The operational straightforwardness of DGNSS has led to its permanent installation and widespread use aboard DP vessels without input from surveyors. This has given vessel operators significant autonomy regarding the positioning of their vessels. When survey services are required on board, the survey contractor is often asked to make use of the DGNSS system permanently installed on the vessel. Whilst usually convenient, this can present potential operational problems relating to the control and performance of the system.

"There is also potential for contractual disputes to arise in any situation where the survey user and the DP user are different companies and where installation, manipulation or reconfiguration of the positioning system for either survey or DP use may impact on the performance of the system for the other party.

"The new IMCA publication addresses all these issues, which are critical from both safety and operational perspectives. The guidelines were produced following discussion and consultation between our Offshore Survey and Marine Divisions. "They set out basic definitions before going on to consider the differing requirements of both surveyors and DP operators. They highlight the potential problems relating to control and performance of the system and the need for planning and co-operation to avoid conflict and ensure safety; and conclude with a set of recommendations for those considering sharing systems."

Notes to Editors (common)

• IMCA is an international association with over 450 members in more than 50 countries, representing offshore, marine and underwater engineering companies. IMCA has four technical divisions, covering marine/specialist vessel operations, offshore diving, hydrographic survey and remote systems and ROVs, plus geographic sections for the Americas Deepwater, Asia-Pacific, Europe & Africa and Middle East & India regions, as well as a core focus on safety, the environment, competence and training. IMCA seeks to promote its members' common interests, to resolve industry-wide issues and to provide an authoritative voice for its members.
• IMCA publishes some 200 guidance notes and technical reports. These have been developed over the years and are widely distributed. They are a definition of what IMCA stands for, including widely recognised diving and ROV codes of practice, DP documentation, marine good practice guidance, the Common Marine Inspection Document, safety recommendation, outline training syllabi and the IMCA competence scheme guidance. In addition to the range of printed guidance documents, IMCA also produces safety promotional materials, circulates information notes and safety flashes.
• Judith Patten is here to help you if you want any additional information on IMCA; would like to discuss a feature article; want to organise interviews with key members of the IMCA team, etc.