Unmanned Systems Maritime Search and Rescue    

      Maritime disasters requiring search and rescue (SAR) operations are always running against a clock.  Those in need of rescuing are usually in need of medical attention, are in danger of succumbing to the elements, or may even be running out of air to breath.  These reasons plus many more are why additional assistance for search and rescue are always welcomed by those tasked with the SAR mission.  There are currently many different systems being developed all over the world to perform different parts of the SAR mission.  For this work the Thunderfish, designed and manufactured by Kraken Robotics, will be discussed.

     Unmanned Looking for Unmanned

     Kraken and its Thunderfish were recently contracted to search Lake Ontario for nine Avro Arrow flight testing models which were lost over Lake Ontario in the 1950s during developmental testing (Rees, 2017). 

Figure 1. Avro Arrow mounted to launch rocket.  (Kraken Robotics, 2017)

As seen in Figure 1, the models being searched for are not much bigger than an adult human.  This mission is a rare occasion for an autonomous underwater vehicle (AUV) to be utilized in a search operation which does not have lives at stake.  These missions allow for those companies designing these types of vehicles to refine their procedures and products for when there are humans who need rescued.  The Thunderfish is a 3.5m long AUV utilizing a titanium hull design meant to withstand a depth of up to 6000m (Kraken Robotics, 2017).  It is propelled using twin brushless motors. 

Figure 2. Thunderfish AUV by Kraken Robotics. (Kraken Robotics, 2017)

Even though the Avro Arrows are only being sought after for placement in museums, the mission to find them is extremely important to Kraken and proving their product can locate relatively small objects on the bottom of a sea floor using the Thunderfish and its embedded sensors.

Thunderfish’s Sensors

            The Thunderfish is equipped with a vast array of different sensors for performing its SAR mission.  Proprioceptive sensors include systems used for navigation and performance monitoring.  On top of the normal sensors needed to maintain awareness on battery health, motor performance, and hull condition, the Thunderfish is equipped with state of the art navigation sensors for maneuvering the vehicle along its search path (Kraken Robotics, 2017).  All of the sensors for monitoring the vehicle are for nothing if there are not sensors on board for detecting whatever the Thunderfish is looking for.  In this case, it is looking for the Avro Arrow models which have been at the bottom of Lake Ontario since the 1950s.  The exact location and condition of each model is unknown requiring multiple sensors to be used for finding them.  Kraken equipped the Thunderfish with their AquaPix Synthetic Aperture Radar and a SeaVision 3D Laser Scanner (Kraken Robotics, 2017).  In addition, it is equipped with a multi-beam echo sounder.  These types of sensors are specifically designed to allow for images to be taken of the sea floor which can quickly be transmitted to the surface where a team can analyze what is being captured. 

Success

            In September 2017, after only a total of 12 days of searching, the first Arrow was located by the team using the Thunderfish.  Figure 3 shows the results of using the AquaPix sonar.

Figure 3. AquaPix image of Avro Arrow flight model on the bottom of Lake Ontario. (Kraken Robotics, 2017)

The success of the Thunderfish where other expeditions had failed shows how AUV technology is beginning to catch up and even surpass manned vehicles.  Vehicles like the Thunderfish, with its amazing sensors can be linked to other unmanned vehicles like unmanned aerial vehicles (UAV) to exponentially increase the SAR effectiveness.  UAVs can give a top down look on the surface of maritime disaster, transmitting coordinates to a maritime vehicle which can then move into position and begin searching and hopefully rescuing.  The advantage unmanned systems have on manned systems is their longevity at the scene.  Other than replacing or charging batteries, the vehicles can stay on station longer than manned vehicles who are limited by their human operator.  Both manned and unmanned systems are capable of employing the same sensors, but the unmanned systems have the ability to keep those sensors looking longer.  The only thing the Thunderfish is lacking is the ability to physically assist a person in distress.  A manipulator arm of some type could be a possible solution to this, at least allowing the Thunderfish to grasp a person and take them to safety.  It will not be long until it is common site at disaster scenes to see humans and robots working as a linked, coherent unit to quickly save lives. 

References

Kraken Robotics. (2017, September 8). Kraken Enables Historic Avro Arrow Discovery. Retrieved     from Kraken Robotics: http://krakenrobotics.com/kraken-enables-historic-avro-arrow-discovery/

Kraken Robotics. (2017, October 23). Thunderfish. Retrieved from Kraken Robotics: http://krakenrobotics.com/products/thunderfish/

Marine Executive. (2016, December 16). Unmanned Vehicles Could Aid Search and Rescue. Retrieved from The Marine Executive: https://maritime-executive.com/editorials/unmanned-vehicles-could-aid-search-and-rescue

Rees, C. (2017, July 18). Kraken AUV to Search for Lost Canadian Test Aircraft. Retrieved from Unmanned Systems Technology: http://www.unmannedsystemstechnology.com/2017/07/kraken-auv-search-lost-canadian-test-aircraft/