Researchers from James Cook University and the Australian Institute of Marine Science are deploying a sensor network on Davies Reef, off Townsville. The sensors measure water temperature, solar radiation, salinity, pollution levels, etc in order to understand complex marine biological processes and predict future coral bleaching events.

Sensor networks reduce the need for expensive field deployments using marine research vessels

The Technology

With seed funding jointly provided by QCIF and AIMS, Dr Graham Woods from the department of Electrical Engineering at JCU has developed a microwave repeater station with a hybrid power system based on battery, solar and wind power for testing radio communications over the horizon.

Hybrid Power

Total energy requirements to support a 60W microwave link and some instruments are estimated at 100W. The system should be at least triply redundant, given failures due to wind, birds and the salt environment. Solar powers are an attractive solution, however birds foul the panels decreasing the efficiency of the photovoltaic cells. Dr Woods is designing an innovative hybrid power system which will use both wind and solar power in order to provide enough capacity when there is no sun or when the panel is fouled by birds. The solar panel is already in place on Davies Reef and JCU and AIMS have set the wind turbine specifications for a marine environment. The challenge is in integrating the two systems together. The advantages of such a system are reliability and low maintenance.

Where is the technology headed?

Further field testing will determine the optimum frequency range and antenna height needed for high speed microwave communications in the over-ocean environment.  For this, more information is needed on how weather and sea conditions influence the height and stability of tropical evaporation ducts and its effect on communications.

Participants

Dr Graham Woods
School of Engineering, James Cook University

Industry Participant

Stuart Kinninmonth
Australian Institute of Marine Sciences (AIMS)

References

Gossard, E.E.. 1981. 'Clear weather meteorological effects on propagations at frequencies above 1 GHz', Radio Science,16(5): 589-608.

Kerans, A., Kulessa, A.S., Lensson, E., French, G., Woods, G.S. 2002. 'Implications of the evaporation duct for microwave path design over tropical oceans in Northern Australia'. In, Proceedings of Workshop on the Applications of Radio Science (WARS02) Leura, Australia, 20 - 22 February 2002.

Palazzi, C.M., Woods, G. S., Atkinson, I., Kininmonth. 2005. 'High Speed Over Ocean Radio Link to Great Barrier Reef'. In, Proceedings of IEEE TENCON’05, Melbourne, Australia, 21-24 November 2005.