AUV FOR SEARCH & RESCUE AT SEA AN INNOVATIVE APPROACH

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1 AUV FOR SEARCH & RESCUE AT SEA AN INNOVATIVE APPROACH Sathyaram Venkatesan Third Year - B Tech Electronics Communication Engineering SRM University, Kattankulathur, Tamilnadu India v.sathyaram@gmail.com SP1 Abstract Global demand for air travel has increased significantly by the emerging economics. However, the Flight accident is major threat to human life. On many occasions the accident happened when aircraft fly over the ocean, because 71% of the Earth s surface is covered by ocean. This paper describes a proposal to develop full automated underwater vehicle system for Search and Rescue (SAR) application within the golden window of 72 hours. This is supported by automated surface vehicles coordinated from Mission Control Centre, AUV Master& Slave model and computerized algorithm for SAR using mathematical modeling approach to reduce time. This concept can serve as a valuable emergency life-saving technology to save more lives while racing against time in offshore and near shore SAR operations. Keywords Autonomous Underwater Vehicle Workhorse AUV, Search and Rescue SAR, Acoustic positioning, missing aircraft I. INTRODUCTION The search and rescue at Sea is very challenging in the harsh marine environment. The recent technology uses submarine with sonar to listen the ultrasonic signal emitted by the black box for the search operation. This new innovative approach uses the multipurpose Autonomous Underwater Vehicle (AUV) for Search & Rescue at sea using Master -Slave model. This uses a mathematical approach to locate the missing subject and retrieve using multipurpose Workhorse AUVs. The existing Workhorse AUVs are controlled by ship and can operate one or two at a time. From the available literature, there is no specially designed Workhorse AUV for SAR (Search and Rescue at Sea). One of the challenges to be faced is to connect Master and Slave Workhorse AUV at SAR location.previous work describes importance and robust routing mechanism to connect robots [1]. The navigation either by Long-Base-Line (LBL) or Ultra-Short Base Line (USBL) using transponders are selected for effective control. In order to control and navigate the Master and Slave Workhorse AUVs a system is proposed here similar to the system set-up with Typhoon Workhorse AUV, equipped with a USBL/acoustic modem transducer, and a set of acoustic modems anchored on the sea bed. Andrea Caiti et al., [2] experimentally showed the navigation procedure that consisted in first geolocalizing the sea bottom modems through the Workhorse AUV USBL, with the Workhorse AUV at the sea surface in GPS contact. Subsequently, the Workhorse AUV navigates underwater using the USBL. Underwater navigation of Workhorse AUV using integrated navigation system should be cost effective and has less horizontal drift. Since 1979 IMO s Safety of Life at Sea (SOLAS) Convention sets the international mandate for SAR. Global Maritime Distress and Safety System (DMDSS) was established in 1988 to rapidly alert SAR authorities and vessels in the immediate vicinity of any ship in distress using terrestrial and satellite communications Satellite communication is very essential for SAR. For small highly mobile terminals the primary choice is tactical UHF or L-Band, because the wider beamwidths and omni-directional antennas which can be supported at this lower frequency band. Today UHF is widely adopted in support of submarines, aircraft and tactical radio, but its data capability is very limited. By way of example, Inmarsat is widely adopted amongst these smaller platforms which provides up to 450 kbps services over L-Band into Aircraft, UAVs, Submarines, Ships and Land forces. As a prelude this concept proposed the author had two experiments were conducted in the design of AUV. As an intern, at the Indian institute of Technology Madras India, had worked on a color sensing robot which involved sensing the flooring color and project the corresponding color. The objective was also to build a mobile Robot with obstacle avoidance, wall following and line following abilities. The robot also involves in use of multiple sensors such as proximity sensor, Color sensors, encoders, servos and line sensor array. It could wirelessly communicate through zigbee modules to other slave robots and thereby we can extend the functionalities of the slaves and perform varies tasks. Further as a member of SRM AUV student team, involved in the development of SRM University Autonomous Underwater Vehicle called SEDNA which is an undergraduate team of students that developed this AUV for competition and research [6]. The goal of the team was to develop a functioning efficient, robust Autonomous Underwater Vehicle that may be used for research and development along with participating in the annual Autonomous Unmanned Vehicle System International (AUVSI) and the Office of Naval Research (ONR) Robosub Competition at San Diego USA. This experience ignited me to come up with the idea of master and slave configuration of AUV in underwater search and rescue. This present study reveals that the workhorse Autonomous Underwater Vehicle could be used for Search & Rescue at sea by Master and Slave configuration. Further /16/$ IEEE 1

2 Information and communications technologies promise to have a significant impact on safety at sea. In the proposed system Workhorse AUVs could be deployable from aircraft and all communicate via surface vehicle to Mission control centre. In addition airborne UAVs can be deployed to coordinate having feedback mechanism. MAP SAR is a software tool with coordinated methodology exclusively for search and rescue at sea in this following paper, the conceptual design of AUV for SAR and suggested methodology for field operation is described. Further AUV design mechanical, electrical and effective communication are described in detail II. CONCEPTUAL DESIGN The objective of this proposal is to develop fully automated SAR system comprising of multiple underwater robots with surface vehicles and mathematically advanced search tool and UAVs. Considering the golden window of 72 hours available after incident, these Workhorse AUVs need to be designed to be easily deployable at correct location. In this way, Search and Rescue at Sea (SAR) can be more effective modernized and advanced to save lives. III DESIGN OF AUV Seven factors are considered in design of an underwater vehicle. These are buoyancy, hydrodynamic damping, stability, Coriolis, added mass, pressure and environmental factors. Further four main aspects in designing Workhorse AUV are mechanical system design, electrical and acoustics and establishing effective communication and customized software tools. The design concept comprises of surface borne vehicle UAV and underwater Workhorse AUVs. The Vessel will communicate with the Master and Slave Workhorse AUVs and have control and can communicate through satellite telemetry. Using two way communications from Master control room, Ship can be navigated. Aerodynamically stabilized cost effective UAV (Drones) can be employed which are interlinked with Surface Vehicles that are floating at sea and linked to Mission control Center AUV Coordinate system An underwater vehicle has 6 degrees of freedom; three spatial coordinates: x, y, z; and three attitudes Euler angles roll, pitch and yaw. Most vehicles are designed to be able to handle as many degrees of freedom as possible. Electrical configuration The electrical configuration is designed to have motion control feature and to have sonar and vision processing feature to measure the vehicle s depth and to discern the vehicle s attitude. Workhorse AUV should measure the vehicle s surge velocity and also shall detect hull breaches with sufficient power for ample testing periods and designed to be highly efficient Mechanical System Design In designing AUVs, simplicity and modularity are keenly to be considered. In mechanical design, the materials chosen should be cost effective and easily machineable. The electronics module should be compact, advanced, and versatile and possess high functionality. This design should provide dry, watertight hull that facilitates the housing of onboard electronic; components and that is capable of surviving in a saltwater environment; need to provide a static and dynamically stable vehicle with suitable versatility in its motion to accomplish a wide range of tasks ; should possess the ability to be modular and extensible for future missions Communication Software sought to be written in order to remotely control the system via computer. A user interface sought to be developed to communicate with the motors as well as display real time monitor, sensor and controller data. To reduce the difficulty and time required in testing the vehicle, a communications system that obtains real-time feedback from onboard components is required. This system should be able to transmit and receive data, as well as change parameters for the vehicle For retrieving lost objects, employing multiple slaves under the sea along with the master robot enables time saving and efficient work. Power system of Workhorse AUV The battery bank for the Master and Slave Workhorse AUV will be designed with Lithium Ion batteries. Studies related to underwater charging of slave AUVs by docking at critical locations close to USBL transponders are under progress to increase the duration of Search. The proposed AUVs would also be powered by miniature non-chargeable primary power packs for ensuring safe retrieval of Master and Slave AUVs as a safety feature. These AUVs would be mounted with RF beacons and flash lights for easy recovery. The primary power pack will be used only during the unexpected failure of major control system of the AUVs. This result in retrieval of critical data related to the object under search. Precise control of AUV During search activity the Workhorse AUVs control algorithm should run with precise position control. The hydrodynamic coefficients, added mass bias the stability of AUVs. Sliding mode control and higher order sliding mode control methods will be implemented for maintaining the position of AUVs at predetermined location as described by T.Salgado et al., [5] III TECHNICAL SPECIFICATIONS These SAR M and SAR S workhorse AUVs have similar shape like torpedo to minimize drag and simultaneously allows them to be modified with time. They are freely flooded, except pressure hulls that house the batteries, navigation unit, CPU, and dry end of sensor electronics. The outer faring is made of ABS plastic and does not provide any structural support, but optimizes hydrodynamic efficiency The specification proposed is given below: Master AUV-SARM Length 5m Diameter 0.53m Weight(Dry) 800kg Buoyancy 8kg net positive /16/$ IEEE 2

3 Depth Rating(400 bar) Endurance Speed Energy Propulsion 4000m 24 with standard payload Up to 5 Knots 14 kwh Lithium-Ion battery, pressure tolerant, Aluminum Oxygen Fuel cell Gimbaled, Ducted thruster for propulsion and control Navigation INS,DVL,SVS,GPS and USBL tracking with vehicle position updates Communication RF, Iridium and acoustic Ethernet via shore power cable Safety system Fault and Leak Detection, Acoustic tracking transponder Payloads Side Scan Sonar, Magnetometer, Sub bottom profiler, Multibeam Echosounder, Transponder,Color Sensing Module(CSM) Software GUI based Custom Built Data Management 32 GB Removable Data Storage Module (RDSM) Payload Software Data Management Acoustic tracking Transponder. Side scan Sonar, light weight camera. GUI based Custom Built 16 GB Removable Data Storage Module (RDSM) IV SCHEMATICS OF AUV The Master (SAR M) and Six AUVs (SAR S) will work together to collect distribution data. In this manner of coordinated AUVs for a single task is considered highly efficient. In the long run, less power is consumed in using a fleet of mapping AUVs as opposed to a single vehicle. Further if AUV malfunction the SAR operation is not severely jeopardized. In the system proposed using artificial intelligence, the AUVs would be capable of "teamwork." These SAR M and SAR S AUVs are identical in shape structure, and payload. They are capable of searching the bottom and will also construct graphical arrays of sonar image, colour images and co-location data. To transfer their collected data, they would be enabled with acoustic modems transmit data and capable of storing data on an on board computer considering the acoustic modem probably won't be able to transfer the bulk of its data collection in real time. The schematic diagram is shown below in Fig 1. Slave Workhorse AUV is a light weight, portable AUV with turnaround time of less than 15 min equipped with side scan sonar and camera. It should be compact with accurate navigation having rapid turnaround. A. Slave AUV called SARS Length 2m Diameter 0.24m Weight(Dry) 60kg Buoyancy 1kg net positive Depth Rating(400 Bar) 4000m Endurance 12 hours Speed Up to 5 Knots Energy 1.5 kwh Lithium-Ion Battery, Pressure tolerant, Aluminum Oxygen Fuel Cell Propulsion Gimbaled, Ducted thruster for propulsion and control Navigation INS,DVL,SVS and GPS and USBL tracking with vehicle position updates Communication RF, Iridium and acoustic Ethernet via shore power cable Safety System Fault and Leak Detection, Fig. 1a Fig. 1b /16/$ IEEE 3

4 Fig. 1c Fig. 1d Fig 1 a b c and d: Schematic diagram (a) Master (b) Slave (c) Cross Section of Master (d) Cross Section of slave Sensors are located in a structure called the scientific payload. The following sensors proposed CT (Conductivity, Temperature): The conductivity measured is converted to a measure of the salinity. The thermometer is an electronic thermometer, which should have a very large range. Laser scanning; Similar to radar using laser light. Light of green frequency used as it can penetrate greater distances in the murky waters. Side Scanning Sonar; It can measure to a distance of 40 meters on either side of the vehicle. It is cylindrical, and has a length of around 38 cm. usually, the Side Scan Sonar is partially recessed in the vehicle, and is mounted forward of control surfaces to minimize turbulent flow over the transducers. Sub-bottom Profiler: Provides high resolution images of the layers below the seabed, and has a penetration of meters into the sea-floor, and a 100 meter range. It is synchronized with the multi-beam and side scan sonar in order to minimize the effects of interference.. Multi-beam sonar: This measures direct depth, enabling complex underwater features to be mapped with precision and also called as "swathe bathymetry sonar." This has frequency (sampling) of about 240 khz. Magnetometer : Can be attached to get data on missing metallic ferrous object. Also tools for mapping and to pick acoustic signals. But available magnetometer is heavy and miniature equipment is to be designed for SAR Inclinometer: Measures changes in angular alignment, so that the AUV can always ensure that it is traveling upright. Camera: Mounted with lasers to increase its range, Silicon Intensifying Tube camera. Leak Detector: Ensures there are no leaks in the AUV. If there are any leaks the AUV will not launch. This is located in the pressure hull. Altimeter: Measures depth with reference to AUV Obstacle Avoidance used for detection of obstacles and to actuate a series of maneuvers to avoid collision. Docking station A docking station for master AUV with diameter 53cm will be designed for autonomous homing and docking in the open ocean, which included downloading data and uploading a new vision plan, recharging the battery and complete power cycling of the AUV Underwater Transponder This is a new feature available in both master and slave AUV which is not available in any other AUV. AUV master and slave will be equipped with this transponder to detect the signal from ULB from the lost aircraft. The flight recorder comprises of Flight Data Recorder (FDR) and Cockpit Voice Recorder (CVR) as per the international civil aviation organization as required by EUROCAE ED-112. Underwater acoustic beacon are triggered by water immersion, emit an ultrasonic 10ms pulse once per second at 37.5 khz. In flight recorders contain valuable information for accident investigators when an aircraft accident happens at sea, it is difficult to establish the exact location of the aircraft wreckage. Underwater recovery of flight recorders is extremely challenging and requires well planned and timely response and for this purpose, this master and slave concept with underwater flight recorder locator will be very useful and this is not available in this manner in existing AUVs. Color sensing module (CSM) This new feature color sensing module is to be developed would have a special feature to find wreckage of the aircraft which is normally aluminum color. The CSM would detect the color and give approximates shape using image processing technique B. Navigation unit This comprises of Acoustic modem, Inertial Navigation System, laser gyro meter and acoustic equipment for navigation C. Pressure hull They house the dry components under atmospheric conditions and provide buoyancy for the vehicle. The CPU is in the PC104 format, allowing interchangeability and upgradeability of components. PC104 also allows operation of the AUV in the familiar C programming language /16/$ IEEE 4

5 D. Propulsion A single DC, brushless, oil compensated motor powering a single thruster at the stern of the vehicle. Two hydroplanes to add necessary stability to the vehicle, while it accurately maps the terrain E. Energy The AUVs will use lithium ion. Lithium ion is useful here because it can last for up to 7 days without recharging. This is essential, as the Slaves will be operating for long stretches at a time. Lithium ion can be recharged from within the pressure hull, without much danger to the vehicle. Eventually, we would hope to use fuel cells for the battery source. They provide the greatest energy density, and output power, but are currently underdeveloped for subsea application. F. Power The indicative power consumption of the various sensors on board the AUV: Master AUV power budget Conductivity and Temperature sensor - 3 W Obstacle avoidance 10 W Navigation Systems - 5W Electronic components and CPU - 3W Side scan sonar - 8W Magnetometer 8 W Multi-beam sonar - 10W Doppler Velocity Log - 3W Total power of Master AUV = 50W Slave AUV power budget Obstacle avoidance 10W Navigation Systems - 5W Electronic components and CPU - 3W Side scan sonar - 8W Magnetometer - 8W Doppler Velocity Log - 3W Total power of Slave AUV = 37W H Power budget Master and Slave Workhorse AUVs have power for 8 to 10 hours. An underwater docking station is visualized to get Workhorse AUVs charged to continue this work. Workhorse AUVs will have transponder and light to get signal from Black box in case it is lying on sea bed. The Master AUV will be equipped with Multibeam Sonar, Conductivity and temperature sensor whereas the slave AUV would have critical payloads related to SAR and navigation. V SAR OPERATION Identifying the missing object First identifying the location of missing object/aircraft will be done using mathematical model approach using various techniques such as Monte Carlo techniques using Probability distribution. SAR MAP is web based simulation search tool to be developed using all available inputs such as the last transmitted known location and prevailing environmental parameters such as wind, current etc., for possible position of wreckage or missing aircraft or missing ship The search of missing object in Deep Ocean can be carried out using Monte Carlo technique and MAP-SAR in SAR at sea though sea patrol is difficult to conduct, fortunately it s relatively easy in initial positioning so that we can narrow the search area to a small scale and start the surface search. By choosing proper mathematical statistics, algorithm, simulation and multipurpose robots we can make full use of the search planes with different equipment and enhance the efficiency of action. When a plane has gone on the way to a given point, it proves that the probable density distribution obeys Gaussian distribution. Here Gaussian distribution can be defined in from the last known position, the lower the probability to be found. The confidence interval can be reduced by making additional runs of this Monte Carlo model [3] Considering the above a probability search map (Fig 2) is prepared. First step is to formulate as many reasonable hypotheses as possible about what may have happened to the object. Second for each hypothesis, a probability density function for the location of the object was constructed. Then a function giving the probability of actually finding an object in location was prepared. In an ocean search, this is usually a function of water depth- in shallow water chances of finding an object are good if the search is in the right place. In deep water chances are reduced. The above information produces an overall probability density map. A search path which starts at the point of highest probability and 'scans' over high probability areas, then intermediate probabilities, and finally low probability areas. In other words, first search where it most probably will be found, then search where finding it is less probable, then search where the probability is even less (but still possible due to limitations on fuel, range, water currents, etc.), until insufficient hope of locating the object at acceptable cost remains. Now, having known the location of the lost object, we can focus on design of vehicle and thereby rescue techniques. Once location is identified search equipment and tools on board the ship are mobilised Technique proposed uses image processing tool with real time communication with the onboard computer of the ship to enable us to have a rough estimate of the condition of the object and surroundings of the lost object. Further, necessary tasks can be performed by creating multiple slave robots that are connected to the Master robot. The Master is connected to the onboard device in the ship which thereby establishes a closed loop network and necessary actions can be performed over the lost objects for recovery. Fig. 2. Probability search map /16/$ IEEE 5

6 An attempt to design completely automated systems for Search and Rescue (SAR) at sea. The outcome is to develop all necessary software and hardware systems such as MAP SAR tool, SAR-Workhorse AUVs, Workhorse AUV-SV and related shore based Mission Control Centre (SAR MCC) as shown in Fig 3 Fig. 3. Pictorial representation of the proposal VI DESIGN METHODOLOGY This concept visualizes upon identification of probable site, the Ship with Workhorse AUVs (Master and Slave) would reach the site. Then Master and Slave Workhorse AUVs would be deployed. The communication and control to ship then to Master and then to slave would be completely automated with proper control loop established from shore at Mission Control Centre this is similar to Satellite control from control station. The Technique proposed uses image processing tool with real time communication with the onboard computer of the ship to enable us to have a rough estimate of the condition of the object and surroundings of the lost object. Further, necessary tasks can be performed by creating multiple slave robots that s connected to the master robot. The master is connected to the onboard device in the ship which thereby establishes a closed loop network and necessary actions can be performed over the lost objects for recovery. The slaves and the master can intercommunicate with each other using acoustic communication. Vessel Specification In order to handle AUV, suitable vessel with handling facility such as a frame, Deck Gears, Winches, Dynamic positioning with a speed of 20 knots with an endurance of 45 days is preferred The proposed concept of SAR visualizes, six important steps are visualised for this SAR. They are Step1: Navigation of Master and Slave Workhorse AUVs by using USBL technique (Fig. 4) Step 2: Communication between Master Workhorse AUV and ship (Fig. 5) Step 3: Effective survey technique by Master and Slave Workhorse AUV and Ship (Fig. 6) Step 4: Drones for visual search of floating debris (Fig. 7) Step 5: Satellite communication to transmit data to control center to fine tune search location (Fig. 8) Step 6: Simultaneous operation of Ship, Master / Slave Workhorse AUV, Drones and communication with control center (Fig. 9) The effective survey technique by master and slave AUV results in seabed mapping, idea of benthic organisms in the search area, historic debris of ships and planes in the area. The exchange of information between the local world model of each robot, and those of the other robots needs to properly address specific points, such as limited bandwidth, reliability of the acoustic channel, selection of the information to be shared with other vehicles and information merging with previous knowledge of the world. Adaptation plays an important role in providing autonomy. There should be plan when unexpected changing circumstances are faced, whether technical or environmental or when sensor or components fail. Autonomous adaptation requires an autonomous understanding of the environment It is well known that any successful maritime search and rescue (SAR) operation depends on several factors. Among them weather and sea conditions are uncontrollable; other factors can be optimized and made more effective by the employment of information and communications technologies. A system able to localize a vessel in trouble and to define the most efficient plan for search and rescue activities is of great importance for safety at sea. The above methodology is proposed to identify correct location to pick up and retrieve the object lying on the Sea bed; Workhorse AUVs should be equipped with tools VII IMAGINATIVE IDEAS Underwater web Underwater web is new concept to have effective underwater connectivity.this feature can help to communicate and control Master and Slave Workhorse AUVs. Under sea telecommunication cable Another idea is to have global underwater permanent nodes for such positioning using telecommunication under cables. There are cables are laid on the sea bed and could be explored to connect transponders which could be used whenever such critical SAR activities are required. This could be additional use of such cables. Fig.10 shows global submarine cable infrastructure and global air traffic and majority of them are over the sea. An idea was conceived to show the possibility of installing transponders in underwater cable to detect signal from black box in case of accident of aircraft. Black box of Airplane The cockpit voice recorder and flight data recorder (FDR) are generally termed as black box of airplane. It continuously records the flight parameters and stores the data. The FDR monitors parameters such as altitude, airspeed and heading. Both recorders are installed in the most crash survivable part of the aircraft, usually the tail section. Each recorder is equipped with an Underwater Locator Beacon (ULB) to assist /16/$ IEEE 6

7 in locating in the event of an overwater accident. The device called a "pinger is activated when the recorder is immersed in water. It transmits an acoustical signal on 37.5 khz that can be detected with a special receiver. It is proposed that this black box could be designed with floatation collars so that it pops up in sea water in the event of airplane accident over sea. It could be installed with a satellite transponder with GPS module for locating the air crash site. The proposed drones could search these units visually and relay the data to control center. From the literature survey it is found that most of time is spent on locating black box lying on the deep sea bed. An estimate is presented here for developing fully automated SAR system 1. Development of SAR Search tool : $ SAR-Workhorse AUV Master ~#1 : $ SAR-Workhorse AUV Slave #6 no: $ SAR-SV Surface Vehicle and UAV: $ Establishment of Mission control Centre : $ Field test and trials : $ Spares and consumables $10000 REFERENCES [1] Seokhoon Yoon and Chunming Qiao, Cooperative Search and Survey using Autonomous Underwater Vehicles (Workhorse AUVs), IEEE Transactions on Parallel and Distributed Systems, Vol.22, March 2011,pp [2] Andrea Caiti,Francesco Di Corato,B.Allota,Luca Pugi Experimental results with a mixed USBL / LBL system for Workhorse AUV navigation,underwater Communications and Networking, Sept 2014 [3] Lawrence D Stone "Search Theory: A Mathematical theory for finding lost objects" reprinted from Mathematics Magazine, Vol.50, No.5, Nov 1977 pp [4] Russell B. Wynn et al., Autonomous Underwater Vehicles (Workhorse AUVs): Their past, present and future Contributions to the advancement of marine geosciences 2014 [5] T.Salgado Jimenez,J-M Spiewak,P.Fraisse A Robost control Algorithm for Workhorse AUV: based on High Order Sliding Mode [6] Akshay Raj Dayal,Aniket Ray,Abishek Bansal,Aakash Khurana,Malle Veera Goutham SRM University Autonomous Underwater Vehicle Concept and Design of Workhorse AUV Sedna Total : $ Schedule of Developement This project requires specialized experts to work on different inter disciplinary skills on underwater navigation control, mechanical design, software, electrical system etc., Quarterly review and target evolution is planned and the design is linked to fabrication and integration. The full system can be visualized, tested and developed in 3 years. Table 1: Project Schedule CONCLUSION This new concept will have fully automated SAR system to put into operational at sea within 72 hours of golden window. This calls for detailed discussion to effectively develop sub systems for such application. Considering the recent incidents of aircraft falling into the sea, this subject needs to be addressed as a priority. This paper cohesively attempts to provide newer ideas involving software tools and effective control and communication among many underwater and above water automated system. The submarine cables system to be constructed in future could have a module for detecting the 37.5 khz signals from the black box of airplane/ship. ACKNOWLEDGMENT I express my sincere acknowledgement to SRM University for extending full support and thank Workhorse AUV team and Mr B.Kesavakumar and Mr.C.K.Kalaivanan NIOT Chennai for their constant help and encouragement /16/$ IEEE 7

8 Fig. 4. Navigation of Master and Slave Workhorse AUVs using USBL technique Ship Fig. 7. Drones for visual search of floating debris Fig. 5. Communication between Master Workhorse AUV and Ship Fig. 8. Satellite communication to transmit data to control center to fine tune search location Fig. 6. Effective survey technique by Master and Slave Workhorse AUV and ship. Courtesy: Russell B. Wynn et al., 2014[4] Fig. 9. Simultaneous operation of Ship, Master/Slave Workhorse AUV, Drones and communication with control center /16/$ IEEE 8

9 + Fig. 10. Possibility of using submarine cable system for SAR : Superimposition of Global Air Traffic with Submarine Cable Infrastructure (Courtesy: Wikipedia and /16/$ IEEE 9