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• Using submarine cables for climate monitoring and disaster warning: Engineering feasibility study
  • Table of contents
  • Executive summary
  • 1 Introduction
    • 1.1 Introduction to subsea telecommunications cables
    • 1.2 Introduction to the science goals regarding instrumenting cables
    • 1.3 Purpose of this study
  • 2 Existing technology
    • 2.1 Cables
    • 2.2 Repeaters
    • 2.3 Branching units
    • 2.4 Submerged plant
      • 2.4.1 Marine handling requirements for submerged plants
      • 2.4.2 Installed conditions for submerged plant
      • 2.4.3 Pressure seals, material selection and external grounds
      • 2.4.4 Maintenance interval
    • 2.5 Terminal equipment
    • 2.6 System supervision
  • 3 Green repeaters
    • 3.1 Science objectives
    • 3.2 Science instruments
      • 3.2.1 Instrument specifications
      • 3.2.2 Precision
      • 3.2.3 Stability
      • 3.2.4 Polling rate and time stamps
      • 3.2.5 Marine handling requirements
      • 3.2.6 Installed conditions
      • 3.2.7 Pressure seals, material selection and external grounds
      • 3.2.8 Instrument design life
      • 3.2.9 Instrument size
    • 3.3 Scope
  • 4 Shared infrastructure assumptions
    • 4.1 Assumptions regarding instrument design
    • 4.2 Required system elements (baseline design)
    • 4.3 Repeater housing modifications
    • 4.4 Adding one fibre pair
    • 4.5 Electrical power limitations
    • 4.6 Repeater bulkhead modifications
    • 4.7 Science module in the space occupied by amplifier module
    • 4.8 Bi-directional optical transmission to adjacent repeaters
    • 4.9 Science instruments mounted outside pressure housing
  • 5 Supplier responses
  • 6 Possible green repeater design solution
    • 6.1 Science module functions
    • 6.2 Bi-directional optical transmission
    • 6.3 Data Channel Capacity
    • 6.4 Science module electrical power consumption
    • 6.5 Diversity and redundancy
    • 6.6 Reliability
    • 6.7 Optical power budget
    • 6.8 Shore station equipment
    • 6.9 Repeater power dissipation
  • 7 Science instrument design constraints
    • 7.1 Electrical power consumption
    • 7.2 Material compatibility
    • 7.3 Marine handling requirements
    • 7.4 Installed conditions
    • 7.5 Pressure seals and depth rating
    • 7.6 External grounds
    • 7.7 Instrument design life
    • 7.8 Instrument size
    • 7.9 Compatibility between table 1 instruments and section 7 design constraints
      • 7.9.1 Digiquartz paroscientific depth sensor series 8cb
      • 7.9.2 Aanderaa conductivity sensor 4319
  • 8 Product development and quality assurance
    • 8.1 Repeater modifications
    • 8.2 Science instrument development
  • 9 Alternatives
    • 9.1 Separate housings containing instruments
    • 9.2 Separate housings containing connectors
    • 9.3 Use of supervisory channel
    • 9.4 Support for seven sensors
      • 9.4.1 Temperature
      • 9.4.2 Sea current
      • 9.4.3 Salinity/conductivity
      • 9.4.4 Pressure
      • 9.4.5 Seismic
      • 9.4.6 Hydroacoustic
      • 9.4.7 Cable voltage
    • 9.5 Acoustic modems
  • 10 Cost estimate
    • 10.1 Fixed costs
    • 10.2 Unit costs
    • 10.3 Operating costs
    • 10.4 Total cost to implement system
  • 11 Ownership issues
  • 12 Legal issues
  • 13 Military issues
  • 14 Need for international standards
  • 15 Summary of study results
    • 15.1 Advantages and disadvantages of each option
    • 15.2 Power requirements of each option
    • 15.3 Heat dissipation for each option
    • 15.4 Physical size for each option
    • 15.5 Data rate
    • 15.6 Power limitations
    • 15.7 Physical size limitations
    • 15.8 Specific issues relating to measurements
    • 15.9 Required sensor resolution
    • 15.10 Need for standards
    • 15.11 Cost estimate
    • 15.12 Seven sensors
  • 16 Considerations
  • 17 Conclusions
  • Annex
  • Glossary
  • Bibliography