Practical feature-based navigation using Forward Looking Sonar for ROV positioning (October 2015)

Feature-based navigation methods using Forward Looking Sonar (FLS) have gained increased attention from academia over the past decade. The advent of lower-cost and smaller multibeam sonars and higher resolution scanning sonars have greatly contributed to the popularity of this topic for study. Yet, feature-based navigation methods for ROVs utilizing FLS data have not made it offshore in common practice because systems offering practical application are not currently available. Greensea has developed a new approach to feature-based navigation using FLS based on an open software architecture that is both practical and ready for offshore. This new technology can utilize either scanning or multibeam sonar data to provide a positioning and navigation solution for ROVs in structured and semi-structured environments. This capability is significant in that it can enable ROV positioning in very challenging environments where traditional methods would fail, as well as provide a positioning capability with minimal new equipment. A radical benefit of feature-based navigation is that it is inherently drift-free and can correct traditional INS navigation solutions, thus potentially enabling precise positioning and control with low cost navigation sensor suites. This paper provides an overview of Greensea´s technology and presents field results.