High Speed Acoustic Network with 2MHz Carrier Frequency for Seafloor Geodetic Observation Robot System

A new and effective seafloor geodetic observing robot network system, which consists of several submarine stations situated in regions susceptible to interplate earthquakes, has been proposed and is under construction in Japan. In this system high bit rate and low error rate are required when uploading mass observed geodetic data from AUV to its dock without cable connection. We proposed an acoustic network system aimed to realize a transmission bit rate of 500 kilobits per second (Kbps). As the first step, to verify the feasibility of the proposed system, a prototype acoustic network system with 100 kilo bit per second (kbps) high rate and pair to pair protocol (PPP) implementation was developed using Phase Shift Keying (PSK). At that time, a serial line was used for data transmission from the dock to AUV because only one set of acoustic transmitter and receiver was available from our budget. Now not only a new set of two way acoustic communication hardware has been developed, but also the carrier frequency has been raised to 2 MHz from 500 kHz used in the old system. Presently we are trying to achieve 500 kbps high bit rate communication.