Hegarty_2021_Broadening.pdf (24.11 MB)
Broadening out the working footprint of a cabled seabed observatory using an interconnected surface buoy, and examining the potential to achieve similar utility from a stand-alone buoyed platform
thesis
posted on 2022-10-19, 11:00 authored by Aoife HegartyThis thesis describes the extensive study and analysis of a cabled seabed observatory
connection and examination of the potential to achieve similar utility from a buoyed
observatory system. The study then broadens out to investigate the potential to extend the
utility afforded from a buoy to meet the demands of a challenging end user: The example
chosen being the long-term real-time remote piloting of a resident Remotely Operated
Vehicle (ROV). Current ocean observational systems have been identified as being
inadequate by the Intergovernmental Oceanographic Commission (IOC) and the Global
Ocean Observing System (GOOS), needing urgent improvement. In response, this
research is driven by the requirement to extend observations over a broader footprint,
using lower cost upcoming technologies to increase system capacity. This need for
expansion led to a thorough examination of the current capabilities of ocean observation
technologies, identifying areas where additional research is required. The findings
highlight the divide between shore-connected cabled facilities and autonomous platforms
in relation to energy availability, communications capabilities and spatial/temporal
footprint. This necessitates a need for examination as to how this gap can be bridged.
The design and build of a bespoke interconnector, linking the seabed Cabled End
Equipment (CEE) at the Galway Bay Cabled Observatory to an adjacent surface buoy
made it possible to examine the true differences in terms of data availability, energy and
power delivery between the two platforms. Elements of the CEE utility were then
extended (broadened out), including communication with adjacent infrastructure. This
connection allowed analysis of data from the cable and the buoy to set the bar for what a
standalone observatory would be required to equal. A study is then conducted to
determine how lower-cost deep-field functionality could be realised, based on the analysis
of the results from the cabled connection. A hybrid communications system (HF and
Satellite) is proposed, in tandem with a triple hybrid (‘tribrid’) energy generation system
(wind, wave and solar), and modelled outputs are presented using meteorological and
oceanographic data from Galway Bay. The outputs were tested against the requirements
of a challenging end user, i.e. teleoperation of a resident ROV with real time video relay,
low latency requirements and requisite power. The work concludes that low latency
remote presence ROV control is theoretically achievable on a remote platform, using
energy generation, storage and communications system as described. Further in situ trials
are required in future work to validate this across a range of operational conditions in the
ocean.
History
Degree
- Doctoral
First supervisor
Toal, DanielSecond supervisor
Omerdić, EdinNote
peer-reviewed In reference to IEEE copyrighted material which is used with permission in this thesis, the IEEE does not endorse any of University of Limerick's products or services. Internal or personal use of this material is permitted. If interested in reprinting/republishing IEEE copyrighted material for advertising or promotional purposes or for creating new collective works for resale or redistribution, please go to http://www.ieee.org/publications_standards/publications/rights/rights_link.html to learn how to obtain a License from RightsLink.Other Funding information
Cullen Scholarship, Marine Institute IrelandLanguage
EnglishDepartment or School
- Electronic & Computer Engineering
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