Unmanned Systems Maritime Search and Rescue
In the
past several years there have been a multitude of autonomous underwater
vehicles (AUVs) that have been used for search and rescue operations. These operations have ranged from searching
for sunken ships to searching for aircraft that have gone missing in the
ocean. In conducting research on search
and rescue AUVs, the Sentry AUV has shown to be very successful, and has the
capable sensors, to handle these types of missions. Several instances within the past few years
where this has happened is the Sentry finding an ancient shipwreck off the
coast of North Carolina in 2015, and being used to find the voyage data recorder
of El Faro cargo ship in February of 2016 (Eggleston, Van Dover,
& Delgado, 2015; MarEx, 2016) . The Sentry has a multitude of equipment and sensors
it can be fitted with that allows it to be successful on missions in the
maritime environment. The specifications
of the Sentry and sensors that allow it to operate in harsh maritime
environments according to Woods Hole Oceanographic Institution (WHOI) (2015) include:
- An operating depth of up to 6,000 meter (19,685 feet).
- Dimensions of 9.7 feet in length by 7.2 feet in width, and a height of 5.8 feet weighing 2,750 pounds without extra equipment.
- It has an operating range of 38 to 54 miles at a max speed of 2 knots.
- For propulsion it uses 4 brushless DC electric thrusters on pivoting wings with lithium ion batteries with a bus power of 48 to 52 Volts.
- It has an endurance time of 26 to 60 depending on its depth and mission type along with a descent and ascent speed of 50 meters per min for both descent and ascent.
- The Navigation system is USBL Navigation with real-time acoustic communications, Doppler velocity log (DVL), and an inertial navigation system (INS).
- It can be equipped with a vast array of sensors based on the mission.
The sensor
suite includes several proprioceptive and exteroceptive sensors that are
specifically designed for the maritime environment. According to Woods Hole Oceanographic
Institution (2015) Sentry specification sheet these sensors include the
following:
- Nortek Acoustic Doppler Velocimeter
- IXSEA PHINS 1 inertial navigation systems (INS)
- Blueview P900-90 forward looking imaging multibeam sonar
- Reson SVP70 sound velocity probe
- SBE FastCAT 49 conductivity, temperature, and depth sensor (CTD)
- Edgetech 2200-M 120/410kHz side scan sonar, Edgetech 2200-M 4-24kHz sub bottom profiler, and an Edgetech 2205 - 850kHz DF sidescan sonar
In
addition to this it can be fitted with other sensors that are not just specific
to the maritime environment. These
sensors include a magnetometer, an 11 megapixel camera, and an inclinometer (Woods Hole Oceanographic
Institution, 2015) .
In order
for the Sentry to be more successful in search and rescue operations several
modifications could be made to the system.
In my opinion it has a long turnaround time to switch out the payload,
sensors, or other equipment once it is on deck, as the turnaround time is 16
hours (Woods Hole Oceanographic Institution, 2015) . WHOI defines the turnaround time as, “vehicle
on deck to vehicle launch. Turn around
time can include redeployment of the same vehicle” (Woods Hole Oceanographic Institution, 2015) . To me this seems like a long time if the payload
would need to be switched out with different sensors quickly for a certain
mission, especially if time is critical.
In the
beginning of search and rescue operations the Sentry could work in conjunction
with an unmanned aerial system (UAS), and sensors deployed on them to help
locate wreckage or debris of a downed aircraft.
This could be done to help identify areas more quickly where wreckage or
survivors may be located, or areas for search and rescue teams to avoid. UAS could be deployed with thermal imaging
cameras to help search for people or debris that may be on the surface of the
water. Other camera and 3D imagery
sensors on UAS could be used to take pictures and map the surrounding
area. One way this could be done with
the Sentry is through an UAS that is being developed by researchers at John
Hopkins University. Recently researchers
at John Hopkins University Applied Physics Laboratory (APL) have developed a
corrosive resistant UAS, called the Corrosion Resistant Aerial Covert Unmanned
Nautical System or CRACUNS, that can be launched from a UUV at a depth of several
hundred feet under water, which can then provide surveillance from the air in
the area the UUV is located (JHU Applied Physics Laboratory, 2016) . If systems like this continue to be
developed, that can work in cooperation with unmanned maritime systems (UMS),
to make search and rescue operations more efficient, then the opportunities are
limitless.
There are
multiple advantages of using UMS over manned systems. One major advantage I see is that UMS allow
for operations to take place at greater depths with sensors that manned systems
may not be able to operate at. This in
turn puts fewer lives at risk for underwater search and rescue operations that may
happen in harsh underwater environments.
Sonars on unmanned systems allow for maps and imagery of the seafloor to
be created at greater depths than manned vehicles. In some situations, unmanned vehicles may
allow for longer missions, too, since crews of manned vehicles may have to
sleep or rest in the time frame that an unmanned vehicle can conduct a mission
without having to surface.
References:
Eggleston, D., Van Dover, C., & Delgado, J. (2015, July
17). Centuries-Old Shipwreck Discovered Off North Carolina Coast.
Retrieved June 11, 2016, from North Carolina State University: https://news.ncsu.edu/2015/07/shipwreck-2015/
JHU Applied Physics Laboratory. (2016, March 17). New UAV
Can Launch from Underwater for Aerial Missions. Retrieved from https://www.youtube.com/watch?v=o17x3XTA-DM
MarEx. (2016, February 11). Search for El Faro VDR On
Again. Retrieved June 11, 2016, from The Maritime Executive: http://www.maritime-executive.com/article/search-for-el-faro-vdr-on-again
Woods Hole Oceanographic Institution. (2015). Sentry [PDF File]. Retrieved June 11, 2016,
from Woods Hole Oceanographic Institution: file:///C:/Users/sjean/Downloads/16G0099-Sentry_One-Pager_Edits1-screen_172424.pdf
Woods Hole Oceanographic Institution. (2015). Sentry
Specifications & Sensors. Retrieved June 11, 2016, from Woods Hole
Oceanographic Institution: https://www.whoi.edu/main/sentry/specifications-sensors
Woods Hole Oceanographic Institution. (2015). Standard
Turnaround Time Between Vehicle Lowerings. Retrieved June 11, 2016, from
Woods Hole Oceanographic Institution: https://www.whoi.edu/page.do?pid=11256
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