OKI Provides Fixed Measurement Barge "SEATEC NEO" as a Demonstration Field, Supporting Real-Sea Trials for Unmanned Inspection of Offshore Wind Power Facilities Using AUVs and Other Technologies

OKI, in collaboration with Toyo Engineering Corporation (President and CEO: Eiji Hosoi, hereinafter "TOYO"), Nippon Steel Engineering Co., Ltd. (President and Representative Director: Yukito Ishiwa, hereinafter "NSE"), and FullDepth Co., Ltd. (President and CEO: Satoshi Yoshiga, hereinafter "FullDepth"), has conducted demonstration trials aimed at the unmanned underwater inspection of offshore wind power facilities using AUVs (Note 1) and other technologies.

The trials were conducted at "SEATEC NEO," a fixed measurement barge (Note 2) owned by OKI and the only one of its kind in Japan, located in Numazu City, Shizuoka Prefecture. The project organized a future vision for inspection systems that contribute to risk reduction and the transition to unmanned operations in underwater inspections of offshore wind power facilities, and proposed a roadmap for social implementation. This demonstration trial was selected for the "Autonomous Underwater Vehicle (AUV) Utilization Demonstration Project" by the Cabinet Office's Secretariat for the Headquarters for Ocean Policy and was carried out jointly by the four companies.

Overview of the Demonstration Trials In October 2025, demonstration trials combining AUVs, ROVs (Note 3), and ASVs (Note 4) were conducted at OKI's fixed measurement barge, "SEATEC NEO." Inspections of the underwater sections of the observation target (Note 5) were performed using video and sonar (acoustic exploration), and technical and operational challenges (e.g., inspection methods for seabed sections, operational structures, etc.) toward the unmanned and autonomous inspection of offshore wind power facilities were identified. For the background of this trial, scenes from the testing, and detailed results, please refer to the PR video (© Toyo Engineering).

Proposal of a Roadmap for AUV Social Implementation Based on the challenges identified in these trials, the future vision for inspection systems in 2030 and 2040 was examined with the goal of improving efficiency and reducing costs for underwater inspections of offshore wind power facilities. We organized the roles and optimal deployment of marine robotics, such as system configurations combining AUVs and ASVs for autonomous and unmanned wide-area inspection, as well as milestones for early social implementation, including technical development, verification, and long-term implementation testing, and proposed this as a roadmap leading up to 2030.

[Illustration: Future vision of an inspection system utilizing marine robotics such as AUVs envisioned for 2040 (© Toyo Engineering)]

1. Hovering AUVs determine their own position through positioning support from surface reference points and inspect mooring lines, power transmission cables, etc. 2. ASVs receive data collected by AUVs via underwater communication and transmit it to a DX panel. 3. When an AUV's battery level drops, it autonomously moves to a seabed station for charging and data communication. 4. Cruising AUVs determine their own position through positioning support from seabed reference points and inspect the condition of subsea cables using sonar and other sensors.

OKI's Main Initiatives Provision of Demonstration Field and Test Support OKI provided its proprietary fixed measurement barge, "SEATEC NEO," moored in the waters around Uchiura Bay in Numazu City, as a demonstration field. Together with OKI ComEco Co., Ltd. (President and CEO: Ryuji Otsuka, hereinafter "OKI ComEco"), an OKI Group company engaged in marine acoustics-related business, we supported the planning and execution of the tests. By using the barge's mooring chains as the target for underwater inspection, we provided an environment simulating foundation structures such as those for wind power facilities, contributing to the clarification of field applicability and inspection accuracy for robotics technology combining AUVs and other equipment.

Systematization of Underwater Infrastructure Element Technologies and Operational Requirements OKI systematized the technical elements and operational requirements of "underwater infrastructure" (surface/seabed reference points, power supply/charging equipment, communication systems, etc.) that are essential for the smooth operation, autonomous driving, and unmanned operation of AUVs. We also identified challenges for infrastructure construction, such as the installation of reference points for high-precision autonomous navigation, underwater power supply equipment to ensure operational continuity, and the clarification of requirements for underwater-to-surface-to-land communication systems that meet diverse information transmission needs, and organized these as future study topics.

Future Outlook Leveraging the knowledge gained from the development and verification of underwater infrastructure technologies for inspection and maintenance tasks related to offshore wind power using AUVs, OKI aims to build an operational foundation with high availability, reliability, and efficiency. In addition, through the provision of "Marine Test Engineering Services" by OKI ComEco—which supports everything from test planning and safety management to implementation, operation, and data acquisition, alongside our real-sea test environment—we will support long-term implementation tests and iterative verification of marine robotics such as AUVs. Based on the results of these demonstrations, we will work on the standardization of underwater infrastructure and expand collaboration with other business sectors, contributing to the development of the entire marine industry, including the offshore wind power business.

Reference Please check the press releases of each company for their respective roles and detailed information, excluding our company.

TOYO Press Release: Overall project coordination / Compilation of various issues for social implementation and creation of a roadmap / Consideration of service providers and marine data utilization platforms. NSE Press Release: Coordination of demonstration trials / Organization of operational issues for the social implementation of marine robotics such as AUVs / Consideration of service providers and marine data utilization platforms. FullDepth Press Release: Provision and operation of the "DiveUnit 300 Lite" ROV / Organization of technical issues in the development of marine robotics such as AUVs.

Terminology Note 1: AUV (Autonomous Underwater Vehicle) An unmanned underwater vehicle that recognizes its own position and surrounding conditions underwater and moves autonomously. In this trial, "Tri-TON," developed by the Maki Laboratory at the Institute of Industrial Science, the University of Tokyo, was used. Note 2: Barge A barge is a flat-bottomed boat used for transporting heavy cargo within ports, usually towed by a tugboat. Although OKI's underwater acoustic measurement facility is a fixed, non-navigating installation, it is called a "barge" because of its flat-bottomed hull shape. Note 3: ROV (Remotely Operated Vehicle) An unmanned underwater vehicle that dives via remote control. In this trial, the "DiveUnit 300 Lite" manufactured by FullDepth was used. Note 4: ASV (Autonomous Surface Vehicle) An unmanned vessel that navigates the water surface via autonomous control. In this trial, the small vessel "Eight Knot I," equipped with the autonomous navigation platform "Eight Knot AI CAPTAIN" developed by Eight Knot Inc., was used. Note 5: Observation Target In this trial, the underwater section of OKI's fixed measurement barge "SEATEC NEO" was the target of observation.