Application of autonomous underwater vehicle systems in distributed ocean observing networks

The task of characterizing a volume of ocean, seafloor, and/or sub-seafloor has long been the realm of (1) surface vessels using hull-mounted sensors or uniquely configured tow bodies, (2) free floating/drifting systems, and (3) moored sensors. In the last decade, Autonomous Underwater Vehicles (AUVs) have emerged as a viable and efficient means for the complex tasks of oceanographic data collection and seafloor mapping efforts that enable an accurate volume depiction. Geophysical and telecommunication survey companies have also demonstrated the cost-effectiveness of these systems, as evidenced by the growth in commercial inventory to support pipeline or cable route studies. The high operational tempo of these systems is further proof of this growth. Additionally, a broad spectrum of joint government and academia partnerships has sponsored efforts across the globe to develop permanent ocean observing systems in coastal environments. Such systems consist primarily of sensor nodes that are moored in a fixed location and connect to each other and/or a relay node (ocean to surface/land) via a fiber-optic subsurface Ethernet network. As seafloor observing systems move into the deeper water environments, installation costs for fiber networking present fiscal and technical challenges. The application of AUV systems as a mobile node in such networks presents an opportunity for expanding the basic data-mapping mission. This paper discusses efforts to date and elaborates on concepts for integrating AUVs into such networks for the purpose of data recovery, relay, and transfer between other moored, drifting (i.e., profiling floats, gliders), or surface network nodes.