Underwater Measurement System Using of a Wide Base Line System

As the necessity for ocean development further increases in Japan, the development of construction technology for deepwater and off shore conditions has become vital. With a goal of meeting this critical demand, Penta-Ocean has developed an underwater measurement system using of a wide base line protocol, based on its accumulated expertise in maritime construction. The system employs a unique acoustic measurement sequence in which the base line of echo sounder transducers is optically arranged and applied to an artificial upwelling fishing ground construction, located at some about 10km from shore and at a depth of about 75 meters.

Three survey boats being equipped with GPS or echo sounder transducers are optimally provided around a floating crane barge suspending the structure to be set in place. By combining positioning data from GPS and distance surveying data from echo sounder transducers, the location of transponder fitted on the structure can be accurately identified, so that the structure can be placed in the correct position.

Construction operations — from guiding to placing structures in specified position — are fully accommodated by this system. The posture and position of structures are presented in real-time and data can be immediately fed backed to operators.

Transponder can be salvaged and reused after completion of work. Disconnect device is provided on the transponder and is remotely controlled by transmitting acoustic signal from on board. Once receiving the signal, disconnect device will be unfasten a hook holding transponder and allows it to float.