During the recent G8 Summit, the Japanese police decided to protect Tokyo Bay against underwater threats by using a waterside security system based on SeaBat multi-beam sonar systems.

To prevent underwater terrorist attacks and disturbances by activities at the G8 Summit, held in Hokkaido Toyako, Japan, the Japanese police decided to use underwater security sonar to protect the Tokyo Bay and the coast around the Tomari nu-clear power plant situated in the Shakotan peninsula. It was the first time ever that underwater security sonar systems were used this way in Japan. The Tomari nuclear power plant is an important facility and is therefore guarded with increased secu-rity.

Maritime security has been an important issue at recent G8 summits. In 2007 at a summit held in Heiligendamm, 21 activ-ists were arrested when they tried to land from a small boat.

The SeaBat 7112, SeaBat 7111DDS and the SeaBat 7123 sonar systems, were delivered to the Japanese authorities by TOYO Corporation as part of a combined waterside security solution in conjunction with DIDSON.

The SeaBat 7112 system consists of a circular array and projector ensonifying a cylindrical volume of water up to 1,000m across. Designed to detect small targets such as divers with closed circuit re-breather equipment, the systems will track and alert operators of their presence on a geo-referenced map of the area. At close range SeaBat 7112 produced some spectacular images.

A single transmit beam illuminates the entire 360° volume to provide complete sector coverage. Among the available options for SeaBat 7112 is automated detection and tracking software (ADT), which improves the tracking of divers.

The SeaBat 7111 Diver Detection Sonar (7111-DDS) is a high-resolution, forward-looking sonar system operating at 100kHz that illuminates wide horizontal sector coverage ahead of the sonar head assembly. The SeaBat 7111-DDS can be mounted on a surface vessel or remotely deployed on the sea floor and is available in depths ratings of up to 60m, which makes it an excellent low-cost solution for waterside security applications.

The SeaBat 7123 is advanced, COTS-based, high resolution sonar suitable for both commercial and military applica-tions.

The SeaBat 7123 is a triple-frequency, high-resolution, forward-looking sonar system that operates at 110kHz (low fre-quency), 240kHz (high frequency), or 455kHz (very high frequency). The SeaBat 7123 illuminates a 45° to 120° horizontal coverage.