Survey and positioning

Comprehensive geophysical surveys are the foundation for the effective design and construction of marine structures and subsea installations. Our experienced team of hydrographers and geophysicists are supported by an array of modern technology solutions such as multibeam echosounders, sidescan sonar , hull mounted sub bottom profiler, gradiometer and towed-seismic systems to provide the critical insight into seabed and sub seabed conditions.

Surveying for potential UXO on and below the seabed is a critical stage during the planning for any marine installation project. At OEGR our teams regularly perform marine UXO and debris detection surveys with industry standard techniques, utilising multibeam echosounder and sidescan sonar to image the seabed in high resolution and towed gradiometers to detect ferrous objects that lay exposed on the seabed and buried below.

Our team of qualified hydrographic surveyors, supported by a fleet of modern multibeam systems, GNSS and motion reference units allow us to work extensively in the capture of hydrographic data for critical safety of navigation and charting, site characterisation, marine aggregates and dredging operations, coastal protection and pre and post construction surveys.

Nearshore and inland marine geophysical surveys - We are specialists in the conduct of nearshore and inland waterway geophysical surveys. Utilising a variety of techniques and technologies with both small manned and unmanned vessels equipped with GNSS positioning, Multibeam, Sidescan Sonar, Magnetometer and Sub-Bottom Profilers; data can be captured for bathymetric charting, feature and object detection and determination of the shallow seabed geology. Our surveyors have many years’ experience of geophysical surveys for a broad range of projects and applications.

Port and harbour bathymetric surveys - We can offer complete or partial surveys of a port; using multibeam sonar to map below the waterline including the seafloor and quay wall structures, through to laser scanning buildings, pontoons and slipways. Our highly qualified and experienced surveyors are experts in conducting shallow water bathymetric surveys. We can capture precise hydrographic information to support the safety of navigation in compliance with the Port Marine Safety Code. From depth charting to locating submerged obstructions, our team have over 20 years of experience in this field.

Managing and mitigating the risks of UXO during offshore development is something the team at OEGR are able to manage in its entirety. From completing the initial geophysical survey to identify non-UXO and potential UXO objects, we can then perform the inspection to positively identify non-UXO or actual UXO objects. Our survey and positioning team provide surface and subsea positioning solutions across the full range of nearshore and offshore vessels and subsea vehicles involved in pUXO identification, allowing targets to be accurately located, investigated using industry leading techniques, and the seabed to be mapped in high resolution following detonation and removal.

Ground truthing features with archaeological potential identified during initial geophysical surveys is a critical step that our teams can support in full, including the provision of accurate positioning of ROV’s and processing of ROV mounted TSS data to identify concentrations of material. This critical step is used to validate the predictions made in the geophysical data and to inform selection of appropriate mitigation in relation to Archaeological Exclusion Zones (AEZs) during construction works.

Our survey and positioning team are capable of supporting the full array of ROV inspection surveys on subsea structures. This includes providing accurate surface and subsea positioning for the vessel and subsea vehicle, and the ROV survey tooling and data processing required for the performance of high-resolution inspection campaigns using multibeam echosounders, 3D photogrammetry, Sidescan Sonar and video imaging.

Our survey teams provide critical positioning and survey support during seabed preparation campaigns which can include boulder removal, seabed rock installation, trenching and backfilling and Controlled Flow Excavation works. We provide topside vessel positioning and helm display and Subsea positioning and orientation. We can fit and operate survey sensors to provide real-time trench depth monitoring and As-left Multibeam and Depth of Burial surveys.