Unmanned Systems Maritime Search and Rescue
The purpose of this activity is to identify and research an unmanned maritime system (UMS) that has been deployed in search and rescue operations. Specific questions that will be addressed include, the proprioceptive and exteroceptive sensors employed by the UMS, what modification could have made it more successful in its mission, how can UMS be used in conjunction with unmanned aerial systems (UAS) to enhance their effectiveness, and what advantages do UMS have over their manned counterparts? For this project, I have selected the Remus 600 Autonomous Underwater Vehicle (AUV), which was used during the search for the wreckage of Air France Flight 443 from 2009 to 2011.
The Remus 600 AUV is part of the Remus family of systems produced by Kongsberg Maritime. It has a maximum operating depth of 600 m, and an endurance of up to 24 hours of continuous operation. It is powered by a rechargeable lithium ion that powers a two-bladed propeller, at a speed of up to 4.5 knots. Its proprioceptive sensor suite consists of a depth sensor, Global Positioning System (GPS), pitch, roll, and yaw gyros, motor and battery monitoring equipment, and an Inertial Navigation System (INS). The INS is especially important in the underwater environment, as it is the system’s only method of determining position when it is unable to receive GPS. It functions by receiving an initial position, as well as updates when able during the mission, from GPS, and measuring velocity and direction over time, and then calculating its position. A highly modular system, the Remus 600 has a variety of exteroceptive sensors available for employment, to include a sidescan sonar, synthetic aperture sonar, a video camera, echo sounder, fish finding sounder, LED lights and strobes for the cameras, and terrain avoidance sonar (Autonomous Underwater Vehicle, REMUS 600, n.d.). In the search for Air France 447, the three Remus 600s employed in the search utilized a dual frequency side scan sonar. The payload worked by painting a picture of the seafloor, and after almost 2 years of searching, detected the wreckage of the aircraft at a depth of approximately 4300 m (14,000 ft). After searching for the aircraft’s black boxes using surface vessels equipped with Towed Pinger Locaters (TPLs), the three Remus 600s began searching the area in the spring of 2010, finally finding the wreckage in April 2011. While there has been much discussion as to whether the Underwater Locator Beacons (ULBs) on the black boxes were working, there was low likelihood that both failed at the same time, introducing the possibility that the depth of the wreckage may have interfered with the ability of the surface vessels to detect the signal. Had the Remus 600s been employed within the first 30 days of the search, before the ULB batteries were calculated to die, and been equipped with a TPL payload, there would have been an increased likelihood of finding the wreckage faster. This is because the wreckage was found almost exactly at the original starting point of the search. When the Remus systems were finally involved, they began searching a different area. It was only during phase 4 of the search that they returned to the original start point and finally found the wreckage (Stone, 2011).
UMS and UAS can be used to complement each other during long duration searches. While they both possess long endurances, and UAS can search a greater area in a shorter period of time, they cannot search below the surface of the ocean. UMS can conduct the underwater portion of the search with very little direct supervision from the operator, allowing humans to concentrate on other areas. UMS possess many of the same advantages as unmanned systems in other domains over their manned counterparts, excelling at dull and dangerous tasks. UMS such as the Remus 600 can remain submerged at great depths for extended periods of time, without risking human life. Additionally, its small size reduces costs over a manned submarine possessing similar capabilities (Autonomous Underwater Vehicle, REMUS 600, n.d.).
References:
Autonomous Underwater Vehicle, REMUS 600. (n.d.). Retrieved April 01, 2017, from
https://www.km.kongsberg.com/ks/web/nokbg0240.nsf/AllWeb/F0437252E
45256BDC12574AD004BDD4A?OpenDocument
Stone, L. D. (2011). In Search of Air France Flight 447. Retrieved April 01, 2017, from
https://www.informs.org/ORMS-Today/Public-Articles/August-Volume-38-Number-
4/In-Search-of-Air-France-Flight-447