Development of an autonomous surface station for underwater passive acoustic observation of marine mammals

The purpose of this research is to develop a solar-powered autonomous surface vehicle (SASV) for the use of ocean environment monitoring and underwater passive acoustic monitoring of marine mammals. Measuring items of the logger version CTD with optical fast DO sensor are depth, temperature, conductivity, salinity, dissolved oxygen, chlorophyll and turbidity. The authors have also developed kinds of underwater passive acoustic monitoring systems (UPAMSs) for establishing a soundness index of the ocean, and contributing to preventative safety measures for collision avoidance of high-speed vessels and cetaceans. A practical application of the SASV can be watching over swarm intelligent underwater vehicles. This SASV consists of a couple of solar panels with a charge-and-discharge controller, an embedded PC, a couple of thrustors, a GPS device and a 3-axis digital compass for navigation. The SASV can be operated in autonomous control mode and manual control mode by a small game controller. Feature of this small-sized, lightweight and low-cost SASV is easy handling and long-term operation. This paper deals with its design concept, hardware components, control software, and trial run.