In recent years it has become evident that ocean data in time and space is required to make predictions of environmental changes on earth. As one method of acquiring data, we propose a virtual mooring system using an underwater vehicle, and have developed a full-scale test-bed vehicle called "BOOMERANG" which can glide back and forth between the sea surface and the seabed collecting ocean data. Since the results of field experiment in March 2010 were satisfactory, construction on a prototype vehicle for practical use was begun in April 2010. In order to improve reliability and to enable prolonged use, the performance of various pieces of loading apparatus of the vehicle was improved. This paper presents results of the field experiment and details of the construction of the prototype vehicle for practical use.
In recent years predictions of changes in the environment on earth and studies on eco development have become increasingly important. Such predictions necessitate ongoing ocean data in time and space. However, construction of a conventional mooring system requires manpower and great expense. Profiling floats such as Argo floats (Roemmich et. al., 2009) cannot stay at a specific point where a continuous and long-term observation is needed because they float in the current. To solve this problem, a test-bed underwater glider for virtual mooring was constructed at the Research Institute for Applied Mechanics, Kyushu University (Nakamura et. al., 2009). The concept of virtual mooring using an underwater glider is shown in Fig.1. The vehicle that houses various pieces of observation equipment glides back and forth between the sea surface and the seabed collecting ocean data. When the vehicle returns to the sea surface, the measured data is transmitted to a research base by a mobile phone. The vehicle then automatically checks its current position by GPS.