Vehicle Description
REMUS has four main sections: the nose cone, RDI Acoustic Doppler Current
Profiler module, mid-body, and tail. In addition, there are two possible
nose cone configurations: standard and bioluminescence. Click anywhere on
the diagram below for more specific information on that section. You may
also be interested in details on how REMUS navigates.
The bioluminescence nose cone incorporates a Multi-purpose
Bioluminescence Bathyphotometer (MBBP), created through a collaborative
effort between researchers at Cal Poly State University, San Luis Obispo
and the University of California, Santa Barbara. The water intake of the
MBBP is incorporated into the tip of the nose cone in order to prevent
premature stimulation of bioluminescence by the moving vehicle. Water
passes through a series of light baffling turns to minimize light
contamination in the bioluminescence signal. A centrifugal pump drives
the water into an enclosed chamber (500 ml volume) in the MBBP section
where a light baffled photomultiplier tube (PMT) measures stimulated
bioluminescence. A white, reflective coating covers the entire inside
of the chamber in order to increase scattering and maximize the amount
of stimulated light measured by the PMT. As the water passes into the
detection chamber, an impeller mechanically stimulates bioluminescence.
The flow rate through the chamber depends on the rotation rate of the
impeller rotor. This rate is adjusted to achieve residence times of
approximately 1 s and flow rates of approximately 500 ml/s-1.
The Interface section, located behind the MBBP in the bioluminescence
nose cone, incorporates Seapoint® fluorometer and turbidity sensors,
an Ocean Sensors® CTD, and an LBL transducer. The fluorometer has an
excitation wavelength of 470 nm and detects fluorescence of chlorophyll a
at 685 nm. The sensing volume of the fluorometer is approximately 340 mm3.
Sensitivity can be set to one of four gains, and the minimum detection limit
is 0.02 ug Chl a/L. The Seapoint® turbidity sensor can also be set
to one of four gains and measures backscattered light at 880 nm. The
backscattered light is measured between 15 and 150 degrees. Only the
small volume of water within 5 cm of the sensor windows is actually
measured. This volume is determined by the scatterance angles measured
by the photodiode and the angle of light emission from the LED. Data from
the fluorometer, turbidity sensor, MBBP, and CTD are recorded between 2
Hz and 3 Hz and stored on a flash disk on board the vehicle.
The MBBP was designed to replace the standard nose cone with one that
incorporates a water intake. As a result, the vehicle does not have the
ability to operate using USBL navigation with the MBBP installed.
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