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Autonomous Underwater Vehic Secret missions under the world’s o By Dr David Maddison Autonomous Underwater Vehicles (AUVs) need not merely float at the whim of tides and currents. They can travel along predetermined routes for thousands of kilometres. They can search for crashed aircraft or sunken ships, do mineralogical surveys of the ocean floor, measure ocean temperature or salinity and perform many other types of mission. V AST NUMBERS of AUVs are in operation around the world and they are used for anti-submarine warfare, beach and sand migration surveys, underwater cable deployment and route surveys, coastal mapping, environmental monitoring, explosive ordinance disposal, military force protection, underwater mapping and geophysical survey, harbour and port security, hull inspection, acoustic research, inspection, maintenance 14  Silicon Chip and repair of underwater structures, intelligence, surveillance and reconnaissance, marine science surveys, mine countermeasures and mineral exploration. SILICON CHIP has previously covered the Argo buoys in the July 2014 article “Argo: Drones Of The Deep Oceans”. Australia is one of the lead players in the Argo program, involving thousands of AUVs gathering information about temperature, salinity, currents, biological data and other parameters of the world’s oceans. But the Argo AUVs merely float at the whim of the ocean currents. Other AUVs can go where they are programmed to go. They come in a range of body shapes, such as: • biomimetic (emulating a biological organism in form or propulsive method); • blended wing body; • submarine shape; siliconchip.com.au les ceans The earliest example of a modern AUV was the Special Purpose Underwater Research Vehicle (SPURV) developed at the University of Washington in 1957 and operated by the US Navy for research until 1979. It could dive to 3000m and had an endurance of 5.5 hours. A large database of AUVs can be seen at http://auvac.org/ Ocean gliders • oblate (roughly spherical in shape but flattened at the poles); • open-space frame – little attempt at streamlining or covering components; • rectangular; • tear-drop shaped; • torpedo; • torpedo with wings; • crawler (a wheeled or tracked AUV that drives along the sea bed) plus other designs that don’t fit into these categories. siliconchip.com.au Most conventional AUVs cannot travel long distances because of battery limitations. Ocean gliders are AUVs which have hydroplanes (underwater wings) and are designed to travel long distances, unlike drifting devices such as Argo that can only go where currents take them. Ocean gliders work by gliding down from the surface to some specified depth and then rising to the surface where they may transmit their data to a satellite or surface vessel. They then glide down through the depths again, collecting data as they go. The wings enable them to convert some of their vertical motion to forward motion. Thus they follow a sawtooth or sinewave-like pattern to propel themselves forwards along their route of choice. Mission durations can be many months and can cover many thousands of kilometres. An animation of a typical ocean glider can be viewed at: https://youtu.be/J3ViBke2ZQg The first ocean glider was designed in 1960 (by Ewan Fallon) to carry a scuba diver, although the vehicle itself was not autonomous. Typical ocean gliders are controlled by a buoyancy engine powered by a heat exchanger. It uses heat difference between the ocean surface at near air temperature and the lower temperatures in the depths (typically, 2-4°C). Buoyancy engine The thermal engine consists of a heat exchange tube, accumulator, valve manifold and two bladders, one external and one inside the pressure hull. The heat exchange tube comprises an outer aluminium pressure vessel that is filled with a wax which undergoes a phase change (melts or freezes) at 10°C. In the centre of the wax is a flexible hose filled with mineral oil. In operation, the glider dives from the surface by rotating the valve and allowing oil from the external bladder to enter the internal bladder, thereby decreasing the overall volume and causing the vehicle to descend. Prior to leaving the ocean surface, the accumulator, backed by a tank with nitrogen at 3000 PSI, must be charged with oil while the wax in the thermal heat exchange tube is in a liquid state. September 2015  15 Called “Sirius”, this AUV is operated by the Australian Autonomous Underwater Vehicle Facility and is a modified version of a vehicle called “SeaBED”, developed by the Woods Hole Oceanographic Institution in the USA. It’s shown here surveying the coral reefs around Scott Reef, WA. These images were obtained by the Sirius AUV from Ningaloo Reef off WA and show sponge beds at a depth of 80m (the images were taken from a height of 2m above the seabed). Each of these three mosaic pictures is made up from 40 images, 10m long and around 1.5m wide. As the glider dives, it passes through the 10°C thermocline into colder waters and the wax begins to freeze and contract, allowing oil to be drawn into the flexible centre hose in the heat 16  Silicon Chip exchanger from an internal bladder. When the glider reaches 1200m, the valve turns again and the accumulator pushes oil to the external bladder, overcoming the hydrostatic pressure, increasing the vehicle’s volume and causing the vehicle to rise. As it passes through the 10°C thermocline into the warmer surface waters, the wax melts, expanding and forcing the oil in the middle hose out at high pressure into the accumulator, thus re-charging the system for the next dive. Because the energy for freezing and melting the wax comes from the ocean itself, no external power is required. This makes this type of AUV extremely energy efficient as no internal power is needed for propulsion – see http:// auvac.org/configurations/view/51 One author, Christopher Von Alt, has argued that the first AUV was the Whitehead Torpedo designed in 1866 and in service from 1894-1922. It had a range of 700m, could travel at 3m/s and was driven by compressed air. It had a navigation system to keep it at a preset depth and later versions incorporated a gyroscope. Whether it was truly an AUV or not, it was of an overall design still used today for torpedoes and many AUVs. The earliest widely accepted example of a modern AUV was the Special Purpose Underwater Research Vehicle (SPURV) developed at the University of Washington from 1957 and operated by the US Navy for research purposes until 1979. It could dive to 3000m and had an endurance of 5.5 hours. It was used to study underwater acoustics, submarine wakes and dye diffusion (which had relevance to the diffusion of submarine wakes), plus other work relevant to submarines. Its hydrodynamic design was calculated on an analog computer. SPURV weighed 480kg and had a speed of 2.2m/s. While the vehicle could be acoustically controlled from the surface, it could run autonomously in modes such as maintaining a constant pressure (ie, depth) or constantly climb and dive between two different depths in a see-saw manner. There were a number of other early AUVs but these were generally expensive, inefficient or large because the available technology was not really adequate. It was not until the advent of powerful microprocessors in the early 1980s that AUVs became viable. High energy density power sources such as lithium-ion batteries have also contributed to the design of practical AUVs. By 1987, there were six AUVs in operation and a further 15 prototypes under development or construction according to Busby Associates’ “Undersea Vehicle Directory” of that year. IMOS (Integrated Marine Observing System) One of the support organisations for the Argo AUV is IMOS, Australia’s Integrated Marine Observing System (IMOS) – see www.imos.org.au IMOS is a collaborative research organisation supported by the Australian Government and led by the University of Tasmania. It is responsible for the integration and management of data from 10 major facilities operated by nine institutions. Data is collected from the Argo floats, sensors on commercial ships and deep water moorings, ocean gliders, autonomous underwater vehicles, instrumentation stations moored at sea, ocean radar (to monitor surface currents over areas of 150 x 150km of coastal ocean), animal tags and monitors, satellite sensors and wireless sensor networks (eg, networks of sensors such as those installed in the Barrier Reef and which stream ocean data such as temperature and salinity). You can peruse a vast amount of IMOS data at http://imos.org.au/imosdatatools.html If you go to the AUV Images Viewer siliconchip.com.au An Australian ANFOG Seaglider on the deck of a support vessel. A recent trip made by ocean glider sh153 as part of the “Lizard” project off Cooktown, Qld. The 200km trip took 13 days and involved 156 dives. You can follow the journeys of such gliders at https://auv.aodn.org.au/auv/ at https://auv.aodn.org.au/auv/ you can zoom in an area of interest on a map of Australia or select an area from a tracks list and then view images taken on that mission. The two facilities involved with IMOS that utilise AUVs (apart from Argo) are the Australian Autonomous Underwater Vehicle Facility (AAUVF) and the Australian National Facility for Ocean Gliders (ANFOG). Sirius The Australian Autonomous Underwater Vehicle Facility operates an AUV called “Sirius”. This is a modified version of a vehicle called the SeaBED, developed by the Woods Hole Oceanographic Institution in the USA. It is an open space frame design, 2m long, 1.5m wide and 1.5m high. It weighs around 200kg, works to a depth of 700m and can travel at a speed of about two knots, its primary mission being sea-bed mapping and environmental monitoring. Sirius has a 1.5kWh Li-ion battery pack and three 150W brushless DC thrusters. It includes a high-resolution stereo camera; a 330kHz multi-beam sonar; depth, conductivity and temperature sensors; and sensors to measure dissolved organic matter and the amount of chlorophyll present. The navigational suite includes a 1200kHz Doppler velocity log with compass, roll and pitch sensors, an ultra short baseline acoustic positioning siliconchip.com.au system and a forward-looking obstacle avoidance sonar, with GPS for use at the surface. All data is geo-referenced. Typical mission profiles (programm­ ed before launch) include following a particular line (transect) or covering an area with a grid pattern. Typical imaging takes place at a constant height of 2m above the sea floor. ANFOG gliders The Australian National Facility for Ocean Gliders (ANFOG) operates two types of gliders, the Seaglider and the Slocum. You can see a zoomable map showing where ANFOG’s gliders are active at http://anfog.ecm.uwa.edu. au/index.php Seaglider is intended for long duration missions of many months and thousands of kilometres. It was developed by the University of Washington and since May 2013 has been produced under license by Kongsberg Underwater Technology, Inc. (a US division of the Norwegian company). Like other ocean gliders, Seaglider “flies” through the water in a sawtooth-like pattern. It uses its wings for gliding, has adjustable buoyancy and its battery is used as an adjustable ballast to alter pitch and roll. It can operate to a depth of 1000m, is 1.8-2.0m long and weighs 52kg dry. In standard configuration, it has a range of 4600km, involving 650 dives to 1000m, and has a speed of 25cm/s or 0.5 knot. Seaglider is suitable for civilian or military use and can carry a wide variety of sensors. According to Kongsberg, its uses include physical, chemical, biological and tactical oceanography, environmental monitoring, storm monitoring and intelligence, surveillance and reconnaissance. It can also be used as a data gateway, as a navigation aid, for active or passive acoustic monitoring of sealife, for current profiling, and for tracking and data capture from acoustic tags. Typical sensors for biological use are current profilers, conductivity and temperature sensors, WET Labs backscatter/fluorometers, dissolved oxygen sensors and photosynthetically active radiation sensors. Seaglider is also used by the US Navy as part of their Persistent Littoral Undersea Surveillance (PLUS) This view of a disassembled Seaglider shows the main internal components. September 2015  17 An ANFOG Slocum in the water. The rudder assembly at the rear houses antennas for the Iridium phone system, GPS, Freewave (a long range wireless modem) and the ARGOS satellite system. Above: the standard model of the Teledyne Gavia. Depending on configuration, it is typically 1.8m long, has a 20mm diameter, weighs 49kg in air and can travel at around 5.5 knots for about seven hours. with the REMUS 600s, collect their data, surface and transmit the information. This persistent surveillance system is somewhat like a marine version of the US’s ARGUS-IS and related airborne persistent surveillance systems – see www.siliconchip.com. au/Issue/2014/December A Seaglider once held the record for the longest duration ocean glider trip – until that time – of over 5500km in 292 days, set in April, 2010. This record was later surpassed by the Wave Glider, described later in this article. The Slocum Glider The main components of a Slocum glider. Note the highly modular construction which can be extensively customised. This Google Earth map shows the trans-Atlantic crossing (US to Spain) of a modified Slocum glider called “Scarlet Knight”. This was the first time an ocean glider had crossed an ocean. As an indication of the energy efficiency of the ocean glider mode of travel, a typical car would only travel about 10km on the amount of energy that this AUV used to cross the Atlantic. The crossing took 221 days from 27th April 2009 to 4th December 2009 (see project website at http://rucool.marine.rutgers.edu/atlantic/). prototype system designed to surveil large areas of ocean for threats. The latest published information indicates that the PLUS system consists of five 18  Silicon Chip Seagliders and six REMUS 600 AUVs. The REMUS 600s dive deep and collect information on enemy submarine threats. The Seagliders rendezvous Conceived by Douglas Webb, this UAV idea was first published as a futuristic vision in a science fiction article in “Oceanography” of April 1989 by Henry Strommel – see www. webbresearch.com/history_facilities. aspx Slocum was named after the first person to single-handedly sail around the world. It is manufactured by Tele­ dyne Webb Research in the USA and has long range and duration. It has a wide variety of sensors, including those to measure currents, turbidity and chlorophyll (and many others), plus hydrophones to listen to the environment. According to Teledyne Webb Research, uses include improving ocean models, ground truth of satellite imagery, collection of water column data, improvement of data quality during greenfield operations, mapping currents for oil plume migration assessment (eg, DeepWater Horizon), low cost, rapid mobilisation for oil spill mitigation, pipeline monitoring, marine mammal awareness and realtime current monitoring during equipment installation, to stay compliant with current laws and environmental regulations. Slocum’s overall dimensions are 1.79m long x 1.01m wide (wing-tip to wing-tip) x 0.49m in height. The siliconchip.com.au actual hull diameter is 0.22m. It is made of carbon fibre and weighs 52kg. Its maximum depth is 1000m. It has RF and acoustic modems plus Iridium and ARGOS satellite communications. Its typical speed is 35cm/s or 0.68 knots and an optional propeller drive is available. The Slocum Glider was the first ocean glider to make a transAtlantic crossing. Apart from civilian users, the US Navy also uses Slocum. Lt. Cmdr Patrick Cross of the US Navy said that the Navy “use(s) these to characterise the ocean. They’re equipped with sensors that can give us salinity and temperature versus depth, and from that we can get sound speeds. We can feed that data into our MODAS [Modular Ocean Data Assimilation System], run by the Naval Oceanographic Office, and that provides a picture that we provide to our submarines”. Slocum has also been launched and retrieved underwater by US Navy submarines. Surprisingly, of the numerous options available on the Slocum Glider, one of the power sources offered is a battery pack that contains up to 360 “C” size alkaline cells. That would have to be a record for the largest number of “C” cells assembled into a single battery pack! On alkaline batteries, the glider has a range of 600-1500km and 15-50 days duration; on lithium batteries the range is 4000-6000km and the duration 4-12 months. You can get an idea of the options and customisability of the Slocum G2 Glider if you look at the product catalog at www.webbresearch.com/pdf/ G2_Product_Catalog.pdf and follow the section on “Build Your Slocum Glider”. The operators manual can be viewed at www.bodc.ac.uk/data/ documents/nodb/pdf/Slocum _ G2 _ Glider _ Operators _ Manual _ January_2012.pdf Looking for algae on the underside of Antarctic ice Another AUV project with Australian involvement is the study of algae growth underneath Antarctic sea ice. This is important because this growth represents the beginning of the Antarctic food chain. Scientists at Denmark’s Aarhus University along with collaborators at the University of Tasmania used an Icelandic-made Teledyne Gavia AUV to scan beneath Antarctic sea ice, measuring light levels with a radiometer to determine where algae was most likely to grow. Australian scientists modified the vehicle to look upwards and record light levels beneath the ice, contrary to its normal mode of operation of looking down at submerged objects (such as pipelines), looking at bottom sediments and looking for lost aircraft such as AirAsia QZ8501. The Australian Maritime College at the University of Tasmania has A Liquid Robotics Wave Glider SV2, along with a support diver in Hawaii. On the surface is the “float” attached by a tether cable to the “sub” unit. The float component of a Wave Glider (named “Fontaine”) in rough seas. This was one of two gliders that headed for Japan while two others headed for Australia as part of the PacX challenge. Note the solar panels and various antennas. received substantial funding to develop AUVs capable of exploring for hundreds of kilometres under sea ice. The proposed AUV will exceed the capability of the Teledyne Gavia which was capable of travelling Building Your Own Autonomous Underwater Vehicle OpenROV (www.openrov.com/) is a tethered ROV (remotely operated vehicle) and is an open source project which could get you into the world of undersea exploration. A kit is available for purchase from the website for around US$900 which is roughly comparable to the entry cost for a higher-end UAV (unmanned aerial vehicle) – see video at “OpenROV v2.7 Video” https:// youtu.be/3SJhmbqvvW4 OpenAUV (http://openauv.org/) draws from the initial work of OpenROV and aims to develop designs for an open source AUV that can be used by hobbyists, students and scientists. RoboSub is an annual competition siliconchip.com.au established by the Association for Unmanned Vehicle Systems International (AUVSI) Foundation and the US Office of Naval Research (ONR) to advance the development of AUVs and is open to high school and university students from around the world – see www. auvsifoundation.org/foundation/ competitions/robosub/ The compe- tition is held every year in San Diego. The BumbleBee AUV team is a competitor at RoboSub (see www.bbauv. com/)and a video of their latest craft (“Bumblebee Robosub 2015 Video”) is at https://youtu.be/Vvsl2vGhfDg Note that building AUVs or ROVs is significantly more difficult than build- ing UAVs (unmanned aerial vehicles). Waterproofing everything is difficult and unlike when a UAV crashes, where you can usually see what happened and recover the pieces, an AUV just disappears into the water! A simpler alternative to underwater vehicles for hobbyists is robotic sail boats and robotic boats. Another option – if you are really keen – is to buy a basic entry-level commercial ROV system such as the VideoRay Scout Remotely Operated Vehicle (ROV) System which can be purchased for around US$4800 – see http://shop.videoray.com/ shop-front#!/p/39381588/category=0 September 2015  19 A somewhat battered Wave Glider float and “sub” on display in Sydney after its world record long distance trip from San Francisco to Australia. 20-30km – see www.utas.edu.au/ latest-news/utas-homepage-news/ new-autonomous-underwater-vehicle-facility-to-help-drive-the-roboticage-of-antarctic-exploration Liquid Robotics Wave Glider This unusual two-part AUV consists of a “float” about the size of a surfboard that contains solar panels, sensors and communications and control electronics. Then, tethered to the float about 7m below the surface is a “sub” or propulsion platform, to exploit wave energy to drive the UAV forward. The “sub” has a series of hinged wings that rotate to a position angled forward (like “/”) when the sub is pulled upwards by the float as it encounters a wave, causing the sub to move forward. As the sub subsequently descends, the wings rotate to a rearward facing position (like “\”) and the glider again moves forward. How AUVs Navigate AUVs can obtain accurate position fixes using GPS on the surface but GPS and other radio signals are rapidly attenuated underwater. So when below the surface, AUVs use some or all of the following: a digital compass, an Inertial Measurement Unit (IMU), a Doppler Velocity Log (DVL), pressure and depth sensors and a sound speed sensor. Note that in polar regions, magnetic compasses are not effective. A Doppler Velocity Log is a device which uses a series of three or more ultrasonic beams in the x, y and z directions that are reflected from the sea floor or by microscopic particles in the water (such as plankton) to provide estimates of a vehicle’s velocity in relation to the sea floor or the water. If an AUV is on an extended mission, such as an Ocean Glider which regularly surfaces over many months, it will use GPS to confirm its position and correct 20  Silicon Chip any navigational error. More accurate navigation such as for mapping requires an Inertial Navigation System (INS) using laser or fibre-optic ring gyros. An INS will contain an IMU as one of its components. Long, Short and Ultra-Short Baseline acoustic positioning systems are also used. In Long Baseline systems, acoustic beacons are placed on the sea floor at known positions. An AUV or other underwater device interrogates the transducers and they respond with an acoustic signal. Based on the round trip travel time from three or more transducers and by using triangulation, the position of the AUV can be determined. In Short and Ultra-Short Baseline systems no sea floor transponders are needed as these are attached to a surface vessel. In Short Baseline, the transducers are at a spacing of tens of meters so a large vessel is needed. In Ultra-Short systems, all three sensors are in one For a video of this process see “Wave Glider Technology” at https://youtu.be/ xfJq9nQ_m2A PacX was established by Liquid Robotics to send four Wave Gliders across the Pacific from the US to both Japan or Australia, in a competition to see who would make the best use of the data collected on the voyages. The voyages started in San Francisco in November 2011 and one glider, “Papa Mau”, arrived in Australia in November 2012 and the other, “Benjamin”, in February 2013. Benjamin was recognised by the Guinness Book of Records for the longest journey of an autonomous surface vessel (despite being classified as an AUV). It travelled 14,703km, surviving shark attacks, severe weather and currents, arriving near Bundaberg. The Wave Gliders in the PacX challenge each contained a fluorometer to measure such things as turbidity, dissolved organic matter and chlorophyll, a weather station, a sensor to measure water conductivity, temperature and salinity, a dissolved oxygen sensor and a wave sensor. Solar-powered Remote Monitoring System (SRMS) The SRMS (also known as the SAUV II) is a long endurance AUV that recharges its batteries via solar panels when it surfaces but is capable of diving transducer head and phase differences between the different transducers are used to determine the AUV’s location. As an example of the accuracy achievable for navigation in underwater mapping operations, the Monterey Bay Aquarium Research Institute near San Francisco report that their Dorado-class AUV (named the “D. Allan B”) can achieve a real-time accuracy of 0.05% of the distance travelled, with a 50% chance of an accrued navigational error of 5m after 10km of travel and a 1% chance of the error being more than 13m. After post-processing of navigational data, the relative navigation error is less than 3m, so the accuracy is comparable with civilian GPS. Acoustic modems are available to transmit data between a surface vessel and an AUV. However, the data rates are relatively slow, such as 31.2kbit/s over 2000m in favourable conditions, 13.9kbit/s over 3500m, 9.2kbit/s over 6000m and 6.9kbit/s over 8000m. siliconchip.com.au to 500m. It has a number of communication options, can carry a payload of 25kg and can travel at 1-2 knots. Because this vehicle uses a propeller, it is said to have better and more precise directional control than a glider. Typical applications are water quality monitoring, oceanographic measurements such as turbidity, temperature etc, fisheries management, marine environmental monitoring, resource protection, water reservoir mapping, internal waves and shear measurement, gas seepage detection, current profiling and sporting safety (eg, for yacht races). One such AUV, the Tavros #2, even has its own Twitter account – https:// twitter.com/tavros02 or <at>tavros02 – and, in 2012, was sending tweets with its location. The SAUV II from Falmouth Scientific, Inc. This long-endurance AUV recharges its batteries using solar panels whenever it’s on the surface and is capable of diving to 500m. REMUS 100 The REMUS 100 (Remote Environmental Measuring UnitS) is a compact AUV that can be used down to 100m. It is built by Hydroid, a division of the Norwegian company Kongsberg Maritime, for such applications as hydrographic surveys, mine countermeasure operations, harbour security operations, environmental monitoring, debris field mapping, search and salvage operations, fishery operations, scientific sampling and mapping. A typical REMUS 100 weighs 38kg, is 19cm in diameter, 160cm long, has a duration of 8-10 hours and a speed of up to 2.3m/s or 4.5 knots. The military version of REMUS is called “Swordfish” and is used by several navies around the world, including Australia, Belgium, New Zealand, Norway and the United States. For a video of the Royal Australian Navy using this AUV (or presumably the civilian version in this case as it is called REMUS) see http:// video.defence.gov.au/play/txZ29wczovD_kNpkQw7PIHON01uH0GdM or just Google “team remus in solomon islands defence”. Finding crashed aircraft REMUS 6000 AUVs were used in the fourth search for the flight data recorders from Air France Flight AF447 which crashed into the Atlantic Ocean in June 2009 but was not found until May 2011. AUVs have also been used in the search for the wreckage of Malaysian Airways MH370 which disappeared siliconchip.com.au This photo shows one of three REMUS 6000 AUVs used to search for Air France Flight AF447 which crashed into the Atlantic Ocean in June 2009. on 8th March, 2014. This is possibly the biggest maritime search in history and is the most expensive. The Australian Transport Safety Bureau (ATSB) is coordinating the search for MH370. When this aircraft originally disappeared and Australia started the search, the most important thing was first to identify the likely area of the crash and then search for pings from the flight data recorder and the cockpit voice recorder. The search for the pings was undertaken with a towed device (not an AUV) borrowed from the US Navy and called the “Towed Pinger Locator 25”. It was towed by the Royal Australian Navy’s ADV Ocean Shield vessel – see www.navy.mil/navydata/fact_display. asp?cid=4300&tid=400&ct=4 After there was no chance of finding any pings due to battery depletion in the recorders, a search began of the sea floor for plane wreckage. A US Navy Bluefin-21 was operated from ADV Ocean Shield and employed to search 850 square kilometres of ocean in the vicinity of where possible pings were thought to have been heard. This AUV was used until May 29th, 2014. The REMUS 100-S AUV. This “S” model is optimised for hydrographic and offshore surveys and is used by several navies around the world. September 2015  21 The all-important flight data recorder from Air France Flight AF447. It was found at the bottom of the Atlantic Ocean by an AUV and recovered using a Remotely-Operated Vehicle. This debris field from Air France Flight AF447 was imaged using a side-scan sonar from an AUV. Australia then called for tenders for a search operator to continue looking for MH370 and a Dutch contractor, Fugro Survey Pty Ltd, won the tender. Fugro uses two towed (non-AUV) EdgeTech DT-1 towfish and a Kongsberg Hugin 4500 AUV. The AUV is used to search areas that are difficult or inefficient for the towed systems to search. Three Fugro vessels have been variously used in the search. There is the “Fugro Equator” for mapping with a multi-beam echo sounder, the “Fugro Discovery” and the “Fugro Supporter”. We asked the Australian Transport Safety Bureau how much the search was costing (eg, the daily costs) but they said that details of the contract with Fugro were “commercial in confidence”. However, on May 13th this year, www.news.com.au said • Videos On Wave Glider “PacX: San Francisco to Sydney” https://youtu.be/AobmMjgKktY • “Schwimm Roboter Wave Glider Von Liquid Robotics.mp4” https:// youtu.be/Ulkwt_uHWqs • “James Gosling on Wave Glider autonomy” https://youtu.be/BVjnYu6aBFk and “Robot Swims 9,000 Miles From San Francisco to Australia” https://youtu.be/Ti8_Oy9GzNU 22  Silicon Chip Australia’s budget contribution over two years was $79.6 million. That represents a daily cost of around $109,000 for Australia’s share alone. Malaysia is also paying for some of the costs. Video of testing the Bluefin-21 on an unnamed RAN vessel is at http:// video.navy.gov.au/play/xzYW1wczoedWuUqytR7Pw0PtCdCfjnLp or it might be easier to Google the term “Testing of Bluefin-21 Autonomous Underwater Vehicle Navy” Military AUVs As of 2014, military applications accounted for 60% of AUVs produced and demand by 2018 is expected to increase by 40% compared to the 2014 figures. As with other AUVs, military AUVs have limitations based on the available battery power and the communications data rate. Also, as with any underwater acoustics (as might be used by sonar sensors employed to look for enemy targets), acoustic transmission through water is a lot less predictable than radar through air. This imposes limitations on sensors and acoustic data links. Note that many sources refer to military AUVs as Unmanned Underwater Vehicles (UUV), as this is the military term for an AUV. Knifefish is a military AUV designed to operate as a mine sweeper and to specifically replace the US Navy’s Results from MH370 high-resolution bathymetric survey work in colour compared to previous low-resolution satellite data in greyscale. This survey work was done during the initial part of the search to generate an accurate map of the search zone. The data was acquired with a multi-beam sonar operating from a ship and represents a small part of the 60,000km2 survey zone. (Image: ATSB). trained mine-sweeping dolphins and sea lions of the Marine Mammal Program which will be wound up in 2017 after 50 years of operation. The robot is designed by Bluefin Robotics and General Dynamics and is based on the civilian Bluefin-21, the AUV involved in searching for MH370. It is scheduled to enter active service in 2017. Knifefish is a torpedo-shaped design around 6m long, 0.5m wide and weighing 770kg. It is propeller-driven and uses lithium ion batteries, allowing it to operate on missions as long as 16 hours. It uses synthetic aperture sonar siliconchip.com.au US Navy operators with a Bluefin-21 AUV on-board the ADV “Ocean Shield”. This AUV can operate at depths of 4000-6000m for 16 hours at a time and was initially used in the search for Malaysian Airlines MH370. (Image: US Navy). This view shows a Hugin 4500 AUV being deployed from the “Fugro Discovery”. This UAV was also used in the search for Malaysian Airlines MH370 off the Western Australian coast. (Image: ATSB). to search for mines which it recognises from an on-board database. The locations of these mines are marked for later destruction by the combat vessel operating the Knifefish. Legal & moral issues Just as there have been legal and moral issues with respect to Unmanned Aerial Vehicles (UAVs) which have attracted legislative action, there are also issues to be considered with respect to AUVs. Among such questions are who is responsible if the machine is involved in an accident? Might it be the programmer who created its navigation algorithms, the owner or the operator and do the normal maritime laws apply to the operation of AUVs? What if one washes up on a shore or what if someone just grabs one out of the water (is that piracy)? What if they deliberately or accidentally cross international boundaries and what if an AUV is used to commit an offence? How autonomous should AUVs be allowed to become? Will military AUVs be able to engage targets without a “human in the loop”? Such questions are already being asked about landbased autonomous military robots. Already UAVs have been used by criminals to fly drugs from Mexico to the United States (and presumably elsewhere). It is also known that criminals have used both manned private submarines and AUVs to deliver drugs to the USA. Conclusion AUVs have demonstrated an ability to operate for extended periods of time, including the ability to make trans­ siliconchip.com.au While a towed vehicle rather than an AUV, this EdgeTech DT-1 named “Dragon Prince” is being used in combination with an AUV in the search for MH370. It is pictured onboard the “Fugro Discovery”. (Image: ATSB). Incidental discovery of an as yet unknown vessel during the search for MH370. This image, dated 11th May 2015, was taken by a Kongsberg Hugin 4500 UAV launched from the “Fugro Supporter” and is likely to be the wreck of a 19th century merchant sailing ship. The wreck is at a depth of 3900m and the most clearly identifiable feature is the ship’s anchor. (Image: ATSB). oceanic crossings. AUVs are much more cost-effective than traditional surface ships and AUV costs will inevitably continue to decrease. It is expected that more and more environmental monitoring will take place as well as more exploration of the ocean bottom. In addition, there is a major role for military AUVs in surveillance and mine and terrorist counter-measures which may serve to make our world a safer place. SC September 2015  23