ROV OPERATIONS IN LOW- VISIBILITY, CONFINED ACCESS ENVIRONMENTS - USING 3D MODELS AND INERTIAL NAVIGATION TO ENHANCE SITUATIONAL AWARENESS

摘要

Inspection-class ROVs provide an excellent option for confined access underwater investigation, particularly when the project locations, operational depths, and access conditions preclude investigation or intervention by divers. Such situations are frequently encountered in flooded tunnels and pipelines. When operational conditions such as poor visibility, and complicated structural layouts with expected potential obstructions combine to present a strong likelihood for entanglement, exceptional demands are placed on the concept of situational awareness during the deployment and operation of inspection-class ROVs in these environments. On a recent project in a flooded mine in northern Canada, SeaView Systems and SeaVision Marine Services teamed with Nuytco Research Limited to develop a world-class inspection-class ROV solution to investigate the mine in water depths exceeding 1400 feet. By developing fully-georeferenced 2D and 3D models of the mine tunnel system and outfitting a SeaEye Falcon with a Doppler-velocity log-aided Inertial Navigation System, the team used this combination of models and real-time navigation inputs to successfully negotiate a complicated underwater tunnel geometry in order to penetrate approximately 450 feet from the launch point to investigate the tunnel conditions during two separate missions. This strategy of 3D Modeling and aided-Inertial Navigation combined to provide a real-time navigation and operational solution that provided a dramatic improvement in situational awareness under harsh operating conditions. Though applied in an inshore setting, this approach can provide the foundation for similar low-visibility, confined access conditions in the offshore as well.