This report reviews the current approach to demonstrating redundancy on offshore vessels with dynamic positioning (DP) systems, in order to establish whether it meets the requirements for suitable and sufficient risk assessment. The review The review covers the relevant formal requirements and guidelines, recent incident experience, failure modes and effects analyses (FMEAs) and trials reports, consultations with stakeholders in the industry, and a review of approaches used in other industries. It concludes that the current approach is appropriate in principle, although there are several areas of weakness in the way it is applied in practice. In order to make more effective use of FMEAs, the report recommends that management guidance should be developed, to provide an industry standard for how FMEAs of DP systems should be specified, managed, performed, verified and updated. Meanwhile, specific recommendations are made to each stakeholder on some of the key issues that would eventually be covered in the management guidance.
Many electronic dynamic positioning systems that use a variety of technologies, such as laser ranging, UHF signal ranging and satellite ranging, are currently available. With the advances in technology, these systems are undoubtedly becoming more and more accurate. In fact, real-time submeter accuracy using the differential Global Positioning System (GPS) in a boat, aircraft, or ground vehicle is not unrealistic. However, verifying positional accuracy at this level of accuracy of a moving platform is difficult. Close- range terrestraial photogrammetry offers a proven and accepted method for this verification, using mostly off-the shelf components and technology. Such a system is being developed at the U.S. Army Engineer Topographic Laboratories. electronic positioning systems, verification, truth system, photogrammetric test system.