By Melanie Tibbs • JP Cheminade

Rapid developments in technology, including portability, have created opportunities for new approaches to shallow-water hydrographic and bathymetric surveying in recent years. The holy grail is high-resolution imaging and accurate mapping using light, robust, agile, low-power and low-cost solutions.

New to the market for 2025 is Picotech Ltd.’s innovative Podlet multibeam sonar package in combination with Blue Robotics’ BlueBoat USV. Together they form the ultimate one-person-portable survey solution.

A leading innovator for more than a decade, Picotech Ltd. has long been a specialist in the design and manufacture of miniature multibeams. Its products’ small size, low weight, and class-leading power consumption enable rapid mobilization, simple launch and recovery, and long endurance. In 2016, Picotech Ltd. ventured into a new market with the PicoMB-120, which enabled one-person-portable, high-resolution USV multibeam echosounder (MBES) surveys at faster rates in confined spaces. In 2020, Picotech Ltd. released PicoPOD-130, the precursor to Podlet, with a new MBES, which now has a network of global users.

Podlet is a lightweight multibeam package that provides a turnkey solution for International Hydrographic Organization (IHO) Special Order surveys. With low power consumption, it delivers long endurance for seamless, high-precision hydrographic data collection—all in a portable package with a combined mass of just 21 kg. BlueBoat+Podlet fits fully rigged in the trunk of a small hatchback and can be hand-launched and recovered at the point of survey.

Podlet is supported by industry-standard acquisition and processing software: BeamworX, EIVA NaviSuite, Xylem HYPACK, Teledyne PDS, and QPS QINSy. It also offers bathymetry and backscatter (snippets) as standard. Compatible with low-cost RTK base stations such as the Reach RS2 and built to include an SBG Ekinox Micro INS, Podlet is highly competitive at its price point. The system also opens up the world of hydrography to many traditionally land-based geomatics companies.

 

 

Multibeam Sonar Applications

Picotech Ltd.’s multibeam sonars offer unparalleled capabilities in underwater surveying, imaging and mapping. Multibeams revolutionize underwater imaging by focusing and processing multiple beams of sound waves simultaneously. By covering a wider area and capturing more data points than single-beams, multibeam sonars produce highly detailed three-dimensional maps of the seafloor with much greater accuracy. This capability makes them indispensable in various fields, including marine research, underwater archaeology, offshore exploration and hydrographic surveying.

The bathymetry and snippets/backscatter outputs of Picotech multibeam sonars make them vital tools across a wide range of industries and applications. Snippets (backscatter) data outputs come as standard and provide invaluable additional information on bottom type (hardness). This combination means images show the same geographical extents, with each providing a different insight into the same environment.

In the hydrographic sector, Podlet allows for accurate mapping of navigable waterways, harbors and coastal areas. Detailed bathymetric data provide information for safe and efficient maritime navigation, as well as aiding the planning and construction of marine infrastructure projects. IHO Special Order surveys are achievable and routinely carried out all over the globe with PicoMB and Podlet.

 

 

Similarly, in the ports, harbors and marinas sector, PicoMB multibeams play a vital role in bathymetric surveying for both hydrography and dredge support. Podlet with BlueBoat can access areas that larger vessels cannot, causing far less disruption to ongoing port/marina operations and enabling complete surveys to be carried out.

The agility of the system also lends itself to scour and accretion monitoring surveys, which look at spatial and temporal changes in bathymetry following the installation or removal of civil engineering works, such as dams, quay walls, flood defenses, tunnels, and bridges, as well as utilities surveying in aquatic areas, especially where depth, access, or flow rates limit the options for larger sonar systems and/or traditional crewed survey craft.

In the field of marine research, Picotech sonars play a crucial role in studying underwater ecosystems and mapping underwater topography and ecology. They have been used by the University of Southampton for the study of seagrass distribution and Newcastle University for the study of geomorphology in the Mekong Delta, to name just two examples.

In the skilled hands of surveyors, researchers, engineers, and explorers, Podlet unlocks the secrets of the underwater world in areas never before accessible, with unprecedented clarity and precision.

The Celtic Interconnector

A survey system comprising an MBES on a USV was deployed in April 2025 for the Celtic Interconnector cable, which will facilitate the transfer of 700 MW of electricity between Ireland and France, spanning a total distance of 575 km, with 500 km of the cable submerged underwater.

GreenC Marine was hired to handle the construction required to bring the cable ashore. The project involved creating a 95-m cofferdam, within which 4 m of material would be excavated. To ensure accurate dredging levels and maintain the required depths, Tower Software was brought on board to supply GreenC Marine with a survey system.

Tower Software selected Picotech’s Podlet, which integrates the PicoMB13P multibeam echosounder and a high-precision motion reference unit. This system was paired with the Blue Robotics BlueBoat, a compact, one-person-portable USV capable of operating autonomously for up to 6 hr. The Podlet proved ideal for the landfall site, where shallow waters and spatial constraints demanded a small yet powerful solution with sufficient range to meet the project’s unique needs.

The USV performed several key tasks, including confirming the cofferdam’s location, monitoring the dredge depths, and verifying the placement of concrete girders used to secure the pipes in place.

 

 

Dredging in the Baltic

The PicoMB can be a powerful tool in the dredging industry when properly integrated with a reliable USV. In this example, the USV mKurs 2.0 by K2sea in Poland was used for a dredging control survey in February 2025 to provide the dredger crew with information on the progress of the dredging process. The demanding task was performed at the entrance to a South Baltic harbor under significant time pressure.

The Polish dredging company Czerwony Szkwał Maritime Works tested the option of acquiring mid-dredge bathymetric data using the rapidly deployed USV. K2sea was able to provide an affordable solution by integrating the mKurs with the PicoMB131, positioned using SBG Ekinox Micro, along with water column parameters measured by AML Oceanographic sensors.

 

 

Managing Hydroelectric Infrastructure

Swiss company Groupe E is a utility active in the production, distribution, sales and trading of electricity, as well as energy-related services (telecommunications, district heating, public lighting), and it has acquired a French-made Bathydrone USV carrying a PicoMB130. The company uses the Picotech multibeam to measure the siltation level of some of Groupe E’s artificial lakes upstream of hydroelectric dams.

The stakes are high: Sediment deposited at the bottom of bodies of water reduces the volume of water available for electricity production and can compromise the safety of the structures. Previously, Groupe E carried out bathymetry operations using a motorboat.

“This new tool allows us to better document the state of our lakes and be more responsive,” said Project Manager Stéphane Dupont. “It can be deployed quickly, for example, to observe the consequences of a flood. We can also verify certain hypotheses.”

Sediment deposits risk causing dams worldwide to lose nearly a quarter of their storage capacity by 2050, according to a UN study published earlier this year. In Switzerland, dams have already lost approximately 23 percent of their initial capacity. By 2050, this loss could reach nearly 33 percent, according to the study, published in the journal Sustainability. Surveys carried out using PicoMB aboard Bathydrone enable successful dredging projects that lower sediment deposit risk.

Conclusion

The technologies developed by Picotech continue to drive new discoveries and insights in subsurface survey and inspection.

For more information about Picotech’s solutions, visit www.picotech-ltd.com or contact: sales@picotech-ltd.com.

Melanie Tibbs is a director of Picotech Ltd.

JP Cheminade is a director and hydrographic surveyor at Geodesea Ltd.