| 1040 |
The two-man operations team takes the pre-programmed
AUV through the pre-dive checkout. |
| 1045 |
Checkout complete, the service umbilical
is detached and the AUV launch procedure begins. The launch/recover
ramp is deployed, and the vehicle is lowered in the water. |
| 1100 |
The AUV is clear of the vessel and begins
its descent. During the descent, the tracking, navigation,
and acoustic communications systems are operating, as
is the CTD sensors, providing the sound-speed profile. |
| 1120 |
Altitude 100 meters, Depth 2,510 meters,
the AUV drops the descent weight and finishes the descent
with its thruster. The DVL is on and providing bottom-referenced
velocities. |
| 1122 |
Depth 2,583 meters, altitude 30 meters.
The AUV turns on its sidescan/sub-bottom profiler and
swims circles at a fixed altitude. The circles help the
USBL system to localize the AUV for initializing the navigation,
The sidescan and sub-bottom sonars are active, and sending
QC data back to the surface via the acoustic link. All
systems check out OK. |
| 1130 |
Depth 2,585 meters, altitude 30 meters.
The operator releases the AUV, knowing that the navigation,
survey sensors, and communications are all working reliably.
The vehicle begins the first 7-km-long leg of the site
survey, telemetering Q/C data to the surface for evaluation. |
| 1254 |
Depth 2,827 meters, altitude 30 meters.
The AUV makes its first turn (4 meter turning radius)
and begins the 300-meter-long cross-track leg. |
| 1257 |
Depth 2,834 meters, altitude 30 meters.
The AUV makes its second turn, and is now on the second
seven-km-long leg.
The AUV follows the track for a total of 20 hours. Throughout
this process, the vehicle is collecting sidescan and sub-bottom
data along track, continuously logging velocity-over-bottom
with its DVL, and is holding the desired altitude to within
centimeters. QC data streams up to the surface vessel.
Meanwhile, on shipboard, analysts reduce the data from
yesterday's run, and the AUV crew are recharging yesterday's
batteries for tomorrow's swap-out. The team leader reviews
the progress to date, prepares tomorrow's mission, and
finishes up his status report for the night shift before
heading off to dinner. During the evening, preparations
are completed for a rapid turn-around of the AUV in the
morning. |
| 0730 |
Depth 2,913 meters, altitude 30 meters.
This cycle's survey is complete, and (with the batteries
at 12% capacity) the operator commands the AUV to drop
the ascent weight and return to the surface. On the vessel,
the recovery ramp is deployed and the AUV team stands
by. |
| 0800 |
The vehicle is at the surface. Since it
was tracked by USBL through the entire ascent, it is spotted
as it breaches the surface. An operator uses the RF modem
link to drive the AUV to the ramp. The line is attached,
and the AUV is brought on board. |
| 0830 |
The service umbilical is attached. Sonar
data is extracted through the high-speed Ethernet link.
The energy section is swapped out, and the next mission
is downloaded. |
| 0940 |
The AUV and all hands are ready for the
next launch, with a one hour margin for contingencies. |
