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