Unmanned Systems Maritime Search and Rescue

The Malaysian Airlines MH370 disappeared somewhere over the Indian Ocean over four years ago, with all 239 souls lost.  The aircraft was believed to have crashed somewhere between 1,500 kilometers and 2,700 kilometers west of Australia (Figure 1) (A Fantastical, 2018).  The depth of the ocean in this area ranges anywhere from 1,500 meters deep to almost 6,000 meters deep, presenting a huge challenge for any search mission that takes place (Deep, 2014).   Over these past four years, Fugro has mounted a sizeable search, covering over 120,000 square kilometers of ocean floor, for the ill-fated MH370 using autonomous underwater vehicles (AUVs), such as the Bluefin-21, but none have returned any findings.  Many believe that with the amount of time that has passed, all hope of ever finding the missing aircraft on the unusually rugged seafloor has been lost (A Fantastical, 2018). 

Figure 1: Depth profile of Indian Ocean where MH370 was believed to have crashed (Deep, 2014)

One company believes there is still hope.  Ocean Infinity, a Houston, Texas based company has rented out the Seabed Constructor, a research ship, and fitted with eight HUGIN 6000 AUVs.  They believe that by using eight of the HUGIN 6000 AUVs, they will be able to cover over 1,200 square kilometers per day allowing them to search much more quickly than previous efforts have, and thus allowing them to cover considerably more ocean floor over the duration of their voyage.  Her new search area, covering roughly 25,000 square kilometers sits just north of the original search area and has been chosen by experts through careful evaluation of wreckage that has washed ashore since the crash (Figure 2).  If nothing is found, the vessel will then continue even further north a location some independent expert’s thing might yield results (A Fantastical, 2018).  So why did Ocean Infinity choose to launch as unmanned mission?  Well its simply, the ocean is a dangerous place, especially at the depths where they believe MH370 could be.  The HUGIN can stay submerged for up to 60 hours, well longer than any human mission could, and if anything goes wrong with the sub and it is lost no risk to life is seen.  A manned mission does not provide any benefits over an unmanned mission, the sensors are the same.  The only main difference would be duration and analysis.  The only benefit that a human could give is real time data analysis which would allow a manned sub to immediately investigate further if a possible discovery is made.

Figure 2: New search area, based off of wreckage that washed up (A Fantastical, 2018)

The HUGIN 6000 AUV, the vehicle of choice for Ocean Infinity, is made by Kongsberg, a company whose passion lies in the water.  The HUGIN AUV is a highly capable system that can reach depths of up to 6000 meters and that is fitted with numerous sensors for underwater search and surveillance.  Fitted with a massive 300-kilogram lithium-polymer battery pack, each of the eight AUVs will be able to stay submerged for up to 60 hours (A Fantastical, 2018).  This endurance, coupled with a sustainable speed of 3.6 knots will allow the AUVs to cover significant ground on each excursion to the deep (Figure 3).  For search and surveillance, the HUGIN is fitted with multiple sensors specifically made for use in maritime environments.  These sensors include a EdgeTech 2205 side scan sonar, a house made Kongsberg EM 2040 echosounder, an EdgeTech 2-16 KHz bottom profiler, a HD CathX color still camera, a turbidity sensor and a magnetometer (Figure 4).  The AUV is also equipped with an acoustic tether, allowing it to be operated in either a semi-autonomous or fully autonomous manner during its 60 hours missions (HUGIN, n.d.).

Figure 3: Internal view of HUGIN 6000 (HUGIN, n.d.)

Figure 4: External view of HUGIN 6000 (HUGIN, n.d.)

Not all the sensors fitted on the HUGIN are required to search for MH370.  However, three of its exteroceptive sensors are very well suited to the maritime environment that MH370 likely came to its final resting place in.  The bottom scanner, as sonar system, will be used to profile the area below the sub to map the ocean floor and aid in navigation and control, as well as to look for debris.  The EdgeTech 2205 side scan sonar is where the HUGIN really makes its money.  This sonar will be used to scan the ocean floor on each side of the sub and will essentially measure the reflectivity or intensity of the radar signals that return.  Since metal reflects more radar than sand, the aircraft should standout well if it is found.  Then, if a possible metallic object is found, the magnetometer will spring into action to confirm the discovery of metal on the ocean floor.  This data is all stored in internal storage on the sub for evaluation by human’s post mission.  If after human review, something in the stored data presents a possible finding, one of the eight HUGINs will be sent back to that area to a more detailed check and will be assigned to take pictures of the area with its onboard HD camera (A Fantastical, 2018).

While the HUGIN is a highly capable AUV, there are several things that could make it better.  First, is better autonomy for data analysis.  This would allow the sub to scrub through the information that it is collecting in real-time to determine if there is anything of interest on the sea floor.  This would allow the sub to then maneuver and activate its HD camera right away to capture images of any possible findings.  That information could then be stored for human analysis post mission and the sub could resume its original routing.  This would increase the efficiency of the mission by making it so subs did not have to return to locations except in the case of a likely positive discovery.  Another possible upgrade for the AUVs is the addition of unmanned aerial systems (UAS).  Each of the AUVs could be fitted with a communications relay that could send data to an orbiting UAS during short times at the surface throughout its mission.  This UAS could then send that data over the horizon to a mother ship for analysis in more near real-time.  If the data showed something of interest, new instructions could then be relayed back to the sub to gather more information in a specific location.  This could again increase the efficiency of the mission.

References:

A fantastical ship has set out to seek Malaysian Airlines flight 370. (2018, January 02). Retrieved July 13, 2018, from https://www.economist.com/science-and-technology/2018/01/02/a-fantastical-ship-has-set-out-to-seek-malaysian-airlines-flight-370

Deep sea challenge for MH370 search. (2014, April 15). Retrieved July 13, 2018, from https://www.bbc.com/news/world-asia-27033921

HUGIN 6000. (n.d.). Retrieved July 14, 2018, from https://oceaninfinity.com/wp-content/uploads/AUV_Factsheet.pdf