Sensors to Increase the Security of Underwater Communication Cables: A Review of Underwater Monitoring Sensors <s> Multi-Beam Echo-Sounder (MBES) <s> Introduction - Why Submarine Cables? Douglas Burnett, Tara Davenport, Robert Beckman PART I: BACKGROUND Chapter 1 - The Development of Submarine Cables Stewart Ash Chapter 2 - The Submarine Cable Industry: How Does it Work? Mick Green PART II: INTERNATIONAL LAW ON SUBMARINE CABLES Chapter 3 - Overview of the International Legal Regime Governing Submarine Cables Douglas Burnett, Tara Davenport, Robert Beckman PART III: CABLE OPERATIONS - LAW AND PRACTICE Chapter 4 - The Planning and Surveying of Submarine Cable Routes Graham Evans, Monique Page Chapter 5 - The Manufacture and Laying of Submarine Cables Keith Ford-Ramsden, Tara Davenport Chapter 6 - Submarine Cable Repair and Maintenance Keith Ford-Ramsden, Douglas Burnett Chapter 7 - The Relationship between Submarine Cables and the Marine Environment Lionel Carter Chapter 8 - Out-of-Service Submarine Cables Douglas Burnett PART IV: PROTECTING CABLESHIPS AND SUBMARINE CABLES Chapter 9 - Protecting Cableships Engaged in Cable Operations Mick Green, Douglas Burnett Chapter 10 - Submarine Cables and Natural Hazards Lionel Carter Chapter 11 - Protecting Submarine Cables from Competing Uses Bob Wargo, Tara Davenport Chapter 12 - Protecting Submarine Cables from Intentional Damage: The Security Gap Robert Beckman PART V: SPECIAL PURPOSE SUBMARINE CABLES Chapter 13 - Power Cables Malcolm Eccles, Joska Ferencz, Douglas Burnett Chapter 14 - Marine Scientific Research Cables Lionel Carter, Alfred H.A. Soons Chapter 15 - Military Cables J. Ashley Roach Chapter 16 - Submarine Cables and Offshore Energy Wayne Nielsen, Tara Davenport) PART VI: APPENDICES AND KEYWORD INDEX Appendix 1 - Timeline of the Submarine Cable Industry Appendix 2 - Overview of the Major Submarine System Suppliers (1850 -2012) Appendix 3 - Excerpts of Most Relevant Treaty Provisions Keyword Index <s> BIB001 </s> Sensors to Increase the Security of Underwater Communication Cables: A Review of Underwater Monitoring Sensors <s> Multi-Beam Echo-Sounder (MBES) <s> The sediment backscatter strength measured by multibeam echosounders is a key feature for seafloor mapping either qualitative (image mosaics) or quantitative (extraction of classifying features). An important phenomenon, often underestimated, is the dependence of the backscatter level on the azimuth angle imposed by the survey line directions: strong level differences at varying azimuth can be observed in case of organized roughness of the seabed, usually caused by tide currents over sandy sediments. This paper presents a number of experimental results obtained from shallow-water cruises using a 300-kHz multibeam echosounder and specially dedicated to the study of this azimuthal effect, with a specific configuration of the survey strategy involving a systematic coverage of reference areas following “compass rose” patterns. The results show for some areas a very strong dependence of the backscatter level, up to about 10-dB differences at intermediate oblique angles, although the presence of these ripples cannot be observed directly—neither from the bathymetry data nor from the sonar image, due to the insufficient resolution capability of the sonar. An elementary modeling of backscattering from rippled interfaces explains and comforts these observations. The consequences of this backscatter dependence upon survey azimuth on the current strategies of backscatter data acquisition and exploitation are discussed. <s> BIB002
The multi-beam echo-sounder (MBES) is an extension of SBES. Nowadays it dominates hydrography due to its high spatial seabed coverage (usually 100%) at relatively short times. MBES transmits and receives a set (fan) of beams with small individual widths across the platform axis. MBES can measure simultaneously the water depth and the seabed reflectivity (backscatter). MBES provides the seafloor relief from depth measurements. MBES also provides seabed properties from the backscatter signal, being proven to be a reliable indicator of the sediment type. The finite dimension of the beams places a limit on the minimum target size that can be successfully detected   BIB002 . MBESs are routinely used for mapping the seafloor of an area for selecting the optimum route for the installation of underwater cables on the seabed BIB001   . The motivation for considering MBES in this study is twofold: (a) it has the capability to detect objects on the seabed and along the water column; and (b) it can be used to map the seabed where the cables lay, in a fast way and with high resolution. Table 6 presents the main specifications of some identified commercial MBESs.