Review of Autonomous Undersea Vehicle (AUV) Developments 
The operational status of the ROVER can be obtained by interrogating an acoustic transponder 
from a surface ship. The number of pings returned is increased as the ROVER progresses 
successfully through its program. Serious faults are indicated by a return to a single ping. 
Acoustic release and disposable ballast -Two acoustic releases in titanium pressure housings 
are mounted on the after end of the structural frame. Each release activates a remote burnwire 
trigger mechanism that can drop a disposable ballast rod of cold-rolled steel. With the release 
of either burnwire mechanism, the ballast falls between the treads, causing the instrument to 
become positively buoyant and rise off the sea floor. A submersible VHF _ transmitter, 
submersible flasher and flag mounted on the aft end of the ROVER and a second set on the 
mast assembly facilitate location by a ship in the vicinity. In the event of a premature release of 
the ballast there is also an ARGOS satellite transmitter mounted on the top of the ROVER for 
detection and tracking. 
Flotation — The ROVER’s flotation consists of 18 evacuated glass spheres (Benthos, 10 and 17 
inch; Billings, 12 inch) mounted on the structural frame. The floats provide positive buoyancy of 
385 kg, and an additional 41-kg buoyancy is provided by the floats on the recovery mast 
assembly. Syntactic foam was considered as flotation for the ROVER, but the added cost and 
air weight of foam proved excessive for the initial design. The spheres are inspected before 
each deployment for excessive spalling to reduce the chance of implosion. 
Weight and balance - In designing the ROVER it was critical that the instrument not sink too 
deeply into soft sediment, yet still be heavy enough to gain traction for maneuvering. The entire 
instrument weighs 40 kg on the sea floor, which permits optimum mobility with the double-track 
propulsion system. 
ROVER Operation 
The ROVER is deployed from a research ship using the 
ship's crane to lower the instrument into the water. (figure 
12) A "quick-release" system is used to detach the ROVER 
from the crane’s hook. Once released, it takes about two 
hours for the ROVER to sink to the bottom in 4000 meters of 
water. After landing, the current rotor and vane-assembly 
are raised vertical by a lead screw in order to provide 
measurements of current speed and direction while the 
ROVER is on the sea floor. The central controller will 
monitor the current flow for a programmable period (about 
24 hours) to determine predominant current flow direction. 
After the initial current monitoring period, the ROVER will 
wait for the right current flow conditions and then travel oe Benes ae 
upstream in the direction of predominant current flow. This way, any peace! hed instrument's 
tracks stir up will move downstream from the next measurement site. The ROVER will tvpically 
be programmed to move 5-10 meters from site Figure 12. ROVER — Ready 
to site. for Deployment 
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