Bélanger, Joseph François Maurice
Study into the use of the GNSS for maritime structure analysis.
University of Southampton, School of Engineering Sciences,
Certain civilian uses of the Global Positioning System (GPS) now demand levels of
precision exceeding the original military specifications for the system. For example,
at present, GPS is used in surveying, navigation and monitoring applications.
Although GPS has been used previously to monitor the structural integrity of civilian
structures such as bridges and towers, the experimental conditions have one
significant difference: These structures are all immobile allowing for fixed references
to be used.
This research’s ultimate aim was to conduct a feasibility study into the use of
GPS, and of the soon to be deployed Galileo constellation, in structural monitoring
of maritime vessels. Under these conditions, a fixed base station as was used in
previous structural monitoring is not a valid approach. New techniques, or variations
on the current ones, were examined to deal with this lack of a fixed reference.
This thesis considers the simulator that was developed in the early phases of
the project and the results that were generated. An expanded version of the simulator
is then explained, alongside the processes used to model structural deformation
experienced by a ship at sea. Frequency analysis of the simulator results is also performed
and the results detailed. It is found that frequency-domain analysis allows
for the identification of different movements seen on the structure. In addition, an
analysis of the impact the deployment of the Galileo constellation is conducted using
simulation. This simulation found a drop of about 20% in Dilution of Precision
(DOP) over several areas.
This thesis then examines some of the field work, that aimed to measure rigidbody
motion, that was conducted onboard Red Jet 4, a catamaran-type vessel. The
experimental setup is described, and the results are briefly considered.
A method for determining the optimal configuration of the receiver network
is also proposed alongside an algorithm to detect plastic deformation of a vessel
structure. Finally, this report considers the original project objectives and how
these were or were not met. Should sufficient accuracy be achieved by a GPS receiver
network, it is possible to use the system to monitor ship structures.
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