Unmanned Systems in Maritime Search and Rescue Operations

     The autonomous underwater vehicle (AUV) called Bluefin-21 and developed by Bluefin Robotics was recently deployed in the South Indian Ocean in April 2014 by the U.S. Navy to assist in the search for the missing Malaysian Airlines Flight 370. (Bluefin, 2015)  The Bluefin-21 assisted in the search by making use of its EdgeTech 2200-M side scan sonar sensor and a high resolution digital camera with LED strobe built in. (Kozak, 2012) The EdgeTech 2200 side scan sonar operates at both 100 and 400 kilohertz to detect anomalies using the 100 kilohertz, 500 meter range frequency to acquire targets and then switching to the 400 kilohertz, 75 meter range frequency to classify those targets. (Kozak, 2012)  The camera could then be used to photograph targets the EdgeTech2200 had identified as of interest.  The images were then stored on a flash drive which was retrieved after the vehicles mission was complete and reviewed later to determine if it had found the aircraft.  Hopefully in the future there will also be the option to take video and the data storage space will be increased.

     The Bluefin-21’s use of the EdgeTech 2200-M side scan sonar and an ultra-short baseline (USBL) acoustic positioning system are exteroceptive and proprioceptive sensors respectively that are well suited for the underwater environment they operate in.  The USBL acoustic positioning system is used to add further accuracy to the GPS/INS data and is used in circumstances where the deep water, long range tracking of underwater targets is needed. (USBL, 2015)  It works by calculating the position of a subsea target by measuring the range and bearing from a vessel mounted transceiver to an acoustic transponder fitted to the target. 

     The Bluefin-21 in the case of searching for Malaysian Airlines Flight 370 is a great example of how an unmanned system has an advantage over a manned one.  The great toll repetitively searching for long months would have on a manned submarine crew is avoided and the search can also be conducted at a much lower cost than if a manned vehicle was used.  The Bluefin-21 also does not need to have a pressurized hull which reduces the cost of producing the vehicle greatly.  The future use of AUVs in search and rescue missions looks bright with future development ideas like the Hydra program on the horizon.  The Hydra program is a DARPA project that seeks to demonstrate an unmanned undersea system with the capability of launching UAVs and other UUVs into environments quickly around the world. (Keller, 2013)

References

Bluefin-21 Autonomous Underwater Vehicle (AUV), United States of America. (2015). Retrieved June 13, 2015, from http://www.naval-technology.com/projects/bluefin-21-autonomous-underwater-vehicle-auv/

Keller, J. (2013). DARPA considers unmanned submersible mothership designed to deploy UAVs and UUVs. Retrieved June 13, 2015, from http://www.militaryaerospace.com/articles/2013/07/darpa-uuv-mothership.html

Kozak, G. (2012). Use of AUV for Deepwater Shipwreck Search. Retrieved June 13, 2015, from http://www.bluefinrobotics.com/assets/Papers/Use-of-AUV-for-Deepwater-Shipwreck-Search-Sea-Technology-Sept2012.pdf

USBL - All Systems. (2015). Retrieved June 13, 2015, from http://www.sonardyne.com/products/positioning/usbl-all-systems.html