Underwater observing systems that collect information with a two or three spatial dimensions
(water current vectors for example) generally measure these parameters relative to their own
orientation. This sensor package orientation is usually determined in-situ via compass sensors that
measure the magnetic orientation of the sensing package, or alternately using radio signals such as
GPS to infer orientation. However sensing systems placed on the sea floor near the north or south
magnetic pole cannot use magnetic sensors, as there is limited horizontal magnetic field in these
locations. Additionally, GPS signals do not penetrate to the seafloor, rendering radio orientation
options unavailable. This presentation describes a system utilising a mini fibre optic gyroscope
sensor to sequentially determine the orientation of a series of ADCP based current measurement
systems deployed on the sea floor in Antarctic water near the magnetic south pole.