A prototype multibeam frontal-scan sonar system has been developed for the characterisation and observation of the seafloor. This system has been developed within the framework of the COSMOS Project (Characterisation and Observation of the Seafloor with a New Multibeam Front-Scan SOnar System; Ref. MAS3-CT97-0090) and represents significant progress in the use of acoustical methods for observing and analysing areas of the sea floor. This new system can be used to survey both the continental shelf and the deep ocean floor, depending on the mounting platform. 

The main technical characteristics of the COSMOS sonar are:

• Horizontal insonification angle of 25º
• Vertical insonification angle of 75º (from nadir to 15º below the horizontal axis)
• Central frequency of 100 kHz
• Simple pulse mode or chirp mode transmission (scan frequency of 3 kHz, and pulse longitude of 8 msec)
• Forward-looking capability about 500 m

Applications

The geological applications of a system such as COSMOS, as well as other applications of  interest to industrial users are:
 

• High-resolution bathymetry in shallow water areas
• High-resolution bathymetry in deep-water areas
• Seafloor type characterisation and sedimentary mapping
• Geological hazard surveying
• Pipeline and cable routing
• Surveying on submerged, man-made structures

Evaluation and validation: actions

Scientific evaluation and validation of the results obtained with the COSMOS system are being carried out by the Marine Geology Group of the Institute of Marine Sciences-CSIC, from Barcelona. These tasks comprise the following actions:
 

• Preparation and definition of the specifications for sea tests
• Data acquisition at sea
• Analysis and interpretation of the acquired data and final evaluation