An unmanned seafloor mapping system: the concept of an AUV integrated with the newly designed USV SEA-KIT

The concept for an autonomous seafloor mapping system for ocean exploration is being built to compete in the Shell Ocean Discovery XPRIZE competition (http://oceandiscovery.xprize.org) by the international team of Nippon Foundation / GEBCO Alumni (see: http://www.gebco-nf.com/). The Team is advised and mentored by selected GEBCO and industry experts, specialized in ocean mapping, geology, software development and naval architecture. The Team is distinguished by its extraordinary diversity with a global distribution of representatives from academic institutions, offshore survey and technology industries, as well as national hydrographic offices. A newly designed, innovative Unmanned Surface Vessel (USV), called SEA-KIT, will be built to cooperate with any Autonomous Underwater Vehicle (AUV) acting as the remote surface access to the deep ocean. The major role of the SEA-KIT in the competition design is 1) the transportation of a commercially available AUV to and from the land launch site to the survey area and 2) the deployment and recovery of the AUV. Additionally, the SEA-KIT surface vessel will offer a positioning solution during AUV operations. Furthermore, if the USV is equipped with hydroacoustic devices, it can function as a stand-alone survey platform for any water depths dependent on the characteristics of the mounted echosounder. Positioning of the SEA-KIT will be realized using the High-Precision Global Navigation Satellite System (GNSS) positioning data. Satellite and radio communication solutions will be used for data transmission between the remote offshore system and the home base (onshore or mothership) components. Communication between SEA-KIT and the AUV will be performed by means of acoustic signals from an Ultra Short Base Line (USBL) device. Those signals are used for positioning and underwater data transmission. This data will be used for continuous AUV position calculation, using information about the AUV position relative to SEA-KIT. SEA-KIT will also be equipped with an Acoustic Doppler Velocity Log (DVL), Pressure Depth Sensor and an Inertial Measurement Unit (IMU). Automated functions for data processing will be considered as a part of the autonomous mapping system operation, due to the large volume of data collected during mission. The existing technologies, providing end-to-end capabilities for the automated processing of the data must be analyzed and evaluated according to the system setup. A significant part of data processing will take place onboard, in order to reduce the difficulties related to the transfer of large amount of data. The operation of the newly designed unmanned and largely autonomous integrated USV-AUV mapping system requires no human intervention on site, which helps to reduce operation costs and move forward to lower-risk, less-effort deep-ocean mapping. This may be the move towards the much needed comprehensive bathymetry mapping of the entire ocean floor, which is in line with GEBCO objectives.