Hydrographic and Geophysical Survey Services

With a solid reputation for delivering quality projects on time and on budget, A-2-Sea has developed a strong in-house survey capability.

A-2-Sea Solutions offers a range of hydrographic, geophysical and UXO survey services, serving clients from various industries including offshore renewables, nautical charting, oil and gas, marine aggregates, and, naturally, subsea cables.

Pre-Construction Geophysical Surveys

A full spread of advanced survey equipment is equipped to provide a detailed, timely and accurate understanding of the development area.

Whether for large area initial reconnaissance, detailed pUXO assessment or determining the safest and most efficient route to shore, our team can acquire the data you need. 

Our team of talented surveyors and geophysicists have experience in working on globally recognised projects, including some of the largest offshore wind farms in the world. We acquire a combination of high-resolution multibeam and side scan sonar data, shallow seismic and magnetometer data to provide a tailored dataset to meet the project requirements. Using sensors from industry leaders such as Kongsberg, Edgetech and Innomar, we create high-quality datasets to inform the next phase of the project. 

Permanently mobilised survey vessels

Land and inter-tidal capability

Rapid mobilisation for survey projects, globally

In-house processing and reporting team

Post-Construction Monitoring Surveys

Using the latest in advanced survey technology, we can monitor the condition of subsea assets, track the development of scour, assess seabed morphology and determine depth of cover. 

For subsea assets, condition monitoring can be both expensive and time-consuming. This data must be managed effectively over the lifetime of the asset to inform crucial decision-making and potentially extend the lifespan. 

We work closely with our clients to ensure we provide the right data at the right time, within budget. Typically this involves the acquisition of high-resolution multibeam bathymetry of up to 700kHz and side scan sonar data of up to 1600kHz. The Kongsberg EM2040 Compact shallow water multibeam (dual head, dual swath configuration), provides 1600 soundings per ping, making it ideally suited for object detection. The dual swath capability allows for increased data density along-track, reducing the survey duration and making the system a more cost-effective option for our clients. A-2-Sea offers alternative high-resolution MBES systems such as the R2Sonic 2024, Reson SeaBat 7125 and Norbit iWBMS.

These core datasets are then supplemented with cable and pipeline depth of burial data - either visual, pulse induction or 3D chirp - as well as ROV visual inspection data.

Land & Intertidal Surveys

To supplement traditional land survey techniques, the use of Unmanned Aerial Vehicles (UAVs) can provide rapid data acquisition for cable landing surveys. 

UAVs are particularly useful for large area surveying, surveying locations where it is either unsafe or inaccessible to access on foot, and for producing high-resolution imagery to provide a greater understanding of the location, which cannot be obtained from traditional techniques. 

Providing up to 1cm horizontal and 1.5cm vertical (+1ppm) positioning accuracy, the Phantom 4 RTK system provides survey-grade results both efficiently and cost-effectively. 

Using the Phantom 4 RTK system, we acquire:

  • 3D Point Cloud data
  • Digital Surface Models (DSM)
  • High-resolution georeferenced Imagery

These datasets are a valuable source of information to inform:

  • Route Engineering
  • Land route inspection
  • Feature identification: including exposed cables in shallow water
  • Shore End installation planning

Autonomous Survey Data Acquisition

We are using Unmanned Surface Vehicles to acquire high-quality survey data both efficiently and cost-effectively. 

Unmanned Surface Vehicles, such as the GeoSwath 4R USV from Kongsberg or the Picotech PicoCAT with PicoPOD, offer remote acquisition in locations where the deployment of conventional platforms is either impractical or hazardous. Systems such as this provide simple, easy deployment and operation, and are a useful addition to supplement and optimise data acquisition on site. 

The GeoSwath 4R is a phase measuring bathymetric sonar delivering high-resolution wide swath bathymetry data with coverage of up to 12 x water depth. With accuracies exceeding IHO standards for hydrographic surveys, the system also acquires co-registered and geo-referenced side scan data to support object detection and bottom characterisation. It is integrated with a GNSS position and heading sensor, a motion reference unit and a sound velocity sensor.

Survey Data Processing & Charting

We use the latest industry-leading processing and presentation software to process and deliver our data in line with client and project requirements. 

Our data QC and processing starts on-site, with onboard data processing facilities enabling rapid turnaround time for the provision of data deliverables. Once the data reaches our office, high-performance processing machines allow us to handle large datasets, delivered in a range of formats. 

As a contractor on the MCA Civil Hydrography Programme, our survey professionals are experienced with processing in CARIS HIPS & SIPS to the UKCHP specification. We use the latest software from providers including QPS, CARIS, SonarWiz and Oasis Montaj, which allows for the production and visualisation of ultra-high resolution survey deliverables.
A team of GIS and CAD specialists deliver quality charting deliverables, including both AutoCAD and ArcGIS charting.

Depending on project requirements, we are experienced in processing and delivering our data using industry-standard software, including:

QPS QINSy & Qimera

Teledyne Caris HIPS & SIPS

QPS Fledermaus

Chesapeake SonarWiz 

IHS Kingdom

Oasis Montaj including UXDetect


Autodesk AutoCAD

Survey Applications

Our team is experienced in providing high-quality survey services for offshore wind farms, wave and tidal developments, from high-specification geophysical acquisition to accurate post-construction monitoring. 

We mobilise a suite of geophysical equipment for pre-construction site investigation, including industry-leading multibeam echosounders, side scan sonars, sub-bottom profiler and chirp systems as well as magnetometer arrays. 

Working with experienced contractors, we supplement our core offering with benthic, environmental and shallow geotechnical investigation. 

Post-construction monitoring typically consists of high-resolution multibeam bathymetry, side scan sonar and visual inspection data. We employ a range of acoustic and ROV techniques for cable depth of burial monitoring, providing a flexible and cost-effective service.

We perform pre-installation cable route surveys from Beach Manhole to beach Manhole using a full spread of advanced geophysical and geotechnical equipment. We can also offer topographical surveys between the Beach manhole and the Cable Landing Station utilising traditional topographical survey techniques and drones.

We can also provide benthic and environmental investigation and shallow geotechnical work to inform route engineering and burial assessment studies using trusted partners.

Our team are experienced in delivering surveys to the Maritime and Coastguard Agency as part of the United Kingdom Civil Hydrography Programme. 

We are comfortable working to relevant related standards; HM Operational Guidance (HMOG's) NP145, The Mariner's Handbook (NP100), and our data meets and typically exceeds International Hydrographic Organisation S-44 standards.

Our offering includes high-resolution multibeam and side scan sonar surveys for acoustic pipeline inspection, identifying areas of exposure and freespan. We also perform depth of burial tracking using both ROV and geophysical techniques. 

We offer a range of both ferrous and non-ferrous pUXO survey services. From magnetometer and gradiometer arrays through to 3D chirp technology, we provide cost-effective and efficient acquisition and processing services to ensure the project remains on schedule. 

Download our latest survey services brochure

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Interested in a Career in Hydrographic or Geophysical Surveying?

If you enjoy working in the marine environment and using technology to explore and map the seafloor, then a career in hydrographic or geophysical surveying may be the ideal path for you.

At A-2-Sea Solutions, we specialise in providing high-quality hydrographic and geophysical surveys for many industries, including wind farm developments, cable installations, and the oil and gas sector.

Hydrographic surveying involves utilising advanced sonar technology, positioning systems, and software to collect and analyse data to produce nautical charts, which are essential for the safe and efficient navigation of vessels. On the other hand, geophysical surveying utilises various methods to investigate the geology of and beneath the seafloor.

At A-2-Sea Solutions, we value our surveying team's expertise, who have an unwavering commitment to quality, safety and take pride in delivering exceptional results to our clients. If you're keen on pursuing a career in hydrographic or geophysical surveying, we encourage you to check out our careers page for more information and contact us to find out how you can join our team.

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