The Ocean Technology Test Bed - An Underwater Laboratory

Transcription

1 1 The Ocean Technology Test Bed - An Underwater Laboratory Alison A. Proctor *, Colin Bradley, Emmett Gamroth and Jeff Kennedy University of Victoria - Department of Mechanical Engineering PO Box 3055, Stn. CSC Victoria, BC, V8W 3P6 Canada Abstract The ocean technology test bed (OTTB) will be an engineering laboratory, located on the sea floor. The OTTB will be integrated with the VENUS (Victoria Experimental Network Under the Sea) observatory in Saanich Inlet, on Vancouver Island. It will enable scientific instrument prototyping, ocean technology development and systems engineering. More specifically, it will facilitate research into the technologies required to extend the reach of cabled ocean observatories using underwater vehicles, autonomous instrumentation, and acoustic networks. This project will first develop the necessary infrastructure and then use the installation to conduct research to advance the state of underwater technology for cabled ocean observatories. The infrastructure will provide a 3-D arena in which underwater engineering research can occur. This arena will effectively be a wet lab for engineering research. Inside of the arena, the OTTB will provide power and communication to static instruments and precision tracking for research on dynamic systems, like vehicles. The facility will consist of a retrievable platform connected to the VENUS node, a top-side ROV, and an integrated acoustic system (IAS). The platform will be the backbone of the installation. It will provide an array of ports with power and communication similar to those available on the VENUS and NEPTUNE nodes. However, unlike a typical observatory node, the platform will be easily raised and lowered simplifying the task of deploying instruments for the purpose of testing and development. The platform will be equipped with a video monitoring system allowing for real-time video of any experiment occurring on or near the platform. The top-side ROV will also be a key component of the test facility, providing surface support to the facility. It will be available to complete routine maintenance, move things around, assist in deployments, and to retrieve any wayward experiments. The IAS will provide the precision tracking in the 3-D arena around the installation. It will consist of a number of cabled acoustic monitoring satellites which will be positioned around the OTTB test site. In the systems initial configuration, the satellites will act primarily as receivers and each object in the arena will carry a small self-contained pinger. The satellites will track the pinger through 3-D space using triangulation. This tracking information will be available to the researchers in real-time through the OTTB user interface. The OTTB facility will provide a user interface that can be accessed over the internet, allowing researchers to monitor or conduct tests on their equipment from anywhere in the world. Once the OTTB infrastructure is in place, the project research team will inaugurate it by pursuing research topics related to hybrid autonomous vehicles, autonomous instrumentation and underwater vehicle docking. This facility will provide the tools that outside researchers need to assist in the development of new underwater technologies including: underwater vehicles, guidance, navigation and control algorithms, multiple vehicle cooperation, simultaneous localization and mapping, docking, acoustic communication, and autonomous sensors. Ultimately, the OTTB will be a state-of-the-art research facility and a go to site for any group wishing to do research, development, or testing on underwater technology. Index Terms Cabled Ocean Observatories, Underwater Technology, Autonomous Underwater Vehicles, Underwater Vehicle Docking, Underwater Acoustic Systems, Underwater Positioning T I. INTRODUCTION HE ocean technology test bed (OTTB) will be an integrated laboratory suitable for scientific instrument prototyping, ocean technology development, systems engineering and basic marine science, located on the sea floor. This innovative technology has a broad range of applications to the emerging development of cabled ocean observatory systems internationally. The North- The Ocean Technology Testbed is funded by the Canadian Foundation for Innovation (CFI) and the British Columbia Knowledge Development Fund (BCKDF). * A. Proctor is a PhD student at the University of Victoria and a research engineer for the Ocean Technology Lab. proctora@me.uvic.ca. Colin Bradley is a Professor at the University of Victoria and the Director of the Laboratory for Automation, Communications, and Information Systems Research (LACIR) at the University of Victoria. The Ocean Technology Lab is a subgroup of LACIR. cbr@me.uvic.ca E Gamroth is a research engineer for the Ocean Technology Lab at the University of Victoria. egamroth@uvic.ca. J. Kennedy is a research engineer for the Ocean Technology Lab at the University of Victoria. jkennedy@engr.uvic.ca.

2 2 east Pacific Time-series Undersea Network Experiments (NEPTUNE) and the Victoria Experimental Network Under the Sea (VENUS) are the first multi-node, deep water, cabled ocean observatory initiatives. A successful sustained ocean presence requires a concerted, focused, on-going engineering effort, parallel to and integrated with the science. Because the stakes are high, all elements must be optimized to be robust, reliable, maintainable, integrated, and affordable. This is the inspiration for the OTTB; a readily accessible facility which can be used as an engineering test bed to enable the development of the essential components needed to execute science on VENUS and NEPTUNE. The OTTB concept was developed by leading ocean scientists and engineers at three workshops, sponsored and organized by NEPTUNE Canada over the course of VENUS, led by the University of Victoria, is a shallow-water test bed for NEPTUNE. It is linked by 70 km of fibre-optic cable and will provide continuous biological, oceanographic and geological data from two locations off the southern British Columbia coast: Saanich Inlet, and the Strait of Georgia. The VENUS infrastructure is an ambitious and complex cabled observatory that is truly leading edge. It has required a long design and deployment process because of novel requirements from the research community. Despite the engineering challenges, the first cable, in Saanich Inlet, was laid in December The Saanich Inlet node became operational in February 2006, and the Straight of Georgia Node is projected to come online in October Both nodes are connected, via shore stations, to the Internet and subsequently a Network Operations Centre (located at the University of Victoria) and a Data Management and Archive System (DMAS). It is the world s first interactive seafloor observatory with both live instrument readings and archived data available via the Internet. NEPTUNE Canada will eventually lay 800km of cable with repeaters and branching units scheduled for completion at the end of August 2008 [1,2]. The installation starts at the Port Alberni shore station and the ring will be installed anti-clockwise, starting with the Folger branching unit and spur, then proceeding to ODP 889, Middle Valley, Endeavour, ODP 1027, Barkley Canyon, and then finally the second shore end in Port Alberni. Through VENUS, users have already begun the exploration process; both of the ocean and new data collection methods. Synoptic, multidisciplinary observations from the seafloor and water column are available continuously in real time anywhere on the Internet, and scientists and students can relate their observations to a broad range of current and historical conditions using the multidisciplinary data bank. Ultimately, scientists will be able to change or start measurements in response to episodic events, from their laboratories, at any hour of the day or night. - Phase I - - Phase II - 3-Point Mooring Small Support Vessel 1000m Inspection Class ROV Bottom Tethered ROV HD Camera Tripod Recoverable Platform/AUV Dock AUV 1000m To Shore Station Junction Box Modem VENUS Node Junction Box IAS Control Housing IAS Satellite Fig. 1 OTTB Project Overview

3 3 Fig. 2 MACO A prototype hybrid AUV developed at the University of Victoria A. Phase I-Preliminary Research and Existing Infrastructure Phase I of this project began in September 2005 with the initial funding provided by the CANARIE-Intelligent Infrastructure Program, NEPTUNE Canada, and the British Columbia Innovation Council. This phase of the project has not only produced technical advances in cable ocean observatory technology but it has also supplied a wealth of hands-on experience in tethered vehicle design and engineering support for observatories. The following infrastructure, as shown in Fig. 1, was developed and installed on the VENUS Saanich Inlet node as part of Phase I: A scientific instrument interface module (SIIM) and support platform. A high definition imaging system cabled to the SIIM. An underwater vehicle tethered to the VENUS node via the SIIM. The vehicle, which is remotely controlled through the VENUS node, was utilized for initial research and development on tethering vehicles to nodes and acts as a mobile platform for the high definition imaging project. In addition, a prototype hybrid vehicle, shown in Fig. 2, is in use on a number of other projects [3]. This vehicle is suitable for performing many of the early stage research initiatives and exploring the integrated acoustic navigation, automated docking and acoustic communications. Materials research and system durability research has also been conducted during this initial phase. Issues such as systematic material appraisal, thorough testing, adherence to industry standards, life cycle modeling and risk analysis are critical to success of future projects. Research into the durability of system components, for example: underwater vehicle: (tether, ROV mate connectors and seals), middle-ware (extension cables, electrical-optical converters, SIIMs, and junction boxes), and custom designed instrumentation, subjected to prolonged exposure to the ocean is ongoing. In addition, research into minimizing biofouling on optical windows over long deployments has become a key focus. Ensuring that optical windows remain free of growth is imperative to the success of any science projects using the equipment. B. The Ocean Technology Test Bed The aim of the OTTB project is to implement a sea floor ocean technology laboratory that is a state-of-the-art research facility and a go to site for any group wishing to do research, development, and testing activities; specifically addressing the engineering needs for the future of cabled ocean observatories. For the OTTB, the final outcome of the workshop-based process was the identification of several core technologies that are important to a broad spectrum of the anticipated VENUS, NEPTUNE Canada and the NEPTUNE user communities. The core technologies identified were: Underwater imaging extending the human visual sense into the observatory both for science and for precise geo-referencing. Acoustics systems integrating science (3-D temperature and velocity via acoustic tomography, geodesy, wind, rain, seismic, monitoring marine mammals via ambient sound, surveying and imaging), vehicle navigation and communications. Underwater vehicle development extending our vision and reach robotically to perform tasks ranging from perturbation experiments at hot vent sites to node maintenance. Collectively, these elements extend the capabilities of any observatory beyond the fixed nodes, and are at the core of the OTTB concept.

4 4 Fig. 3 VENUS Saanich Inlet Node The timing for this project is ideal for establishing complementary research programs with other organizations, creating multidisciplinary projects and developing international connections, as other countries consider deploying cabled observatories [4]. The OTTB will be integrated with the existing VENUS node in Saanich Inlet, and will immediately enhance the existing infrastructure s capabilities through the development of new technologies, expanding the scientific research possibilities and fully utilizing the available bandwidth. All of the experimental research opportunities will be powerfully leveraged because of the real-time monitoring possible though the observatory system. The OTTB will also provide a means for researchers to engage in dry runs prior to deploying packages on observatory nodes, as it will employ sensors, vehicles, communications, maintenance, service and management aspects which mirror future NEPTUNE objectives. Ultimately, the OTTB will satisfy a critical need for cabled underwater observatories by: Establishing an integrated test bed which does not exist elsewhere. Significantly reducing the time, cost and risk incurred in developing new technology and undertaking new science. Providing real-time access to the engineering and scientific research which, in turn, will speed the development of the larger networks. The OTTB is an innovative research tool that will enable a new ways of performing science and developing unique technology, and an innovative seafloor laboratory environment for collaborative engineering and science research programs. II. PHASE II - THE NEW OTTB FACILITY The OTTB is Phase II of an ongoing initiative at the University of Victoria to advance marine technology. The OTTB project will be a 3D arena or wet lab in which engineering research can occur. Inside of the arena, the OTTB will provide power and communication to static instruments and precision tracking for research on dynamic systems, such as underwater vehicles. The OTTB will be integrated with the VENUS observatory network located in Saanich Inlet, shown in Fig. 3. The OTTB will be an extension of the existing underwater installation which was installed as part of Phase I as shown in Fig. 1. It will interface to the VENUS node through a wet-mate electro-optic connector provided by NEPTUNE Canada. This is a hybrid connector that has both copper and fibre-optic lines for transmitting power and communications respectively. The project infrastructure, shown in Fig. 1, will consist of the following components: A top-side ROV to provide surface support anywhere inside of Saanich Inlet. A Recoverable Platform providing power and communications to static sensor packages. An integrated acoustic system (IAS) which will provide positioning and communication anywhere inside of the 3-D arena. With these components, the OTTB will have the capacity to be a test facility for outside groups wishing to test their own products. The goal of this project is to make research facilities that are normally only available to the military or very large companies publicly available. The top-side ROV will be a workhorse vehicle capable of carrying sensor packages undergoing evaluation or repositioning experimental equipment. This vehicle will assist in the deployment of the system components and be a tool for research and development once the test bed is operational. The recoverable platform will be providing a simple and accessible way of testing instruments that are intended to be installed on either VENUS or NEPTUNE. The platform will have eight re-configurable ports which can simulate any VENUS or NEPTUNE Canada connection. Also, the test schedule is flexible since the platform is recoverable and extensive surface and underwater support is not required to connect or adjust an instrument. The recoverable platform is discussed in depth in section II-B. Finally, the IAS, presented in section II-C, will turn the OTTB into a 3D AUV test

5 5 arena. Inside the arena, it will be possible to track any static or dynamic object. This will provide any group that would like to test an ROV, AUV, or positioning system with truth data to use in analyzing their results. This is an invaluable tool for validating navigation algorithms or for verifying the accuracy of a prototype positioning system. A. Overview of Recoverable Platform and the Facility Infrastructure The platform will serve as a readily recoverable point of connection to the power and communications offered by VENUS. As such, users will be able evaluate instruments on an ocean observatory for a fraction of the typical deployment cost. Since the platform is easily recoverable, it will also make brief deployments feasible and alleviate the scheduling constraints of other observatories, where scientists must wait for a semi-annual maintenance cruise to make any changes to their instrumentation. The platform will also be equipped with an underwater video system including pan-tilt mounts and lighting. The camera will be controllable via the OTTB user interface and will allow general observation and inspection of the platform and any static instruments undergoing testing. In addition, the camera will provide vital real-time feedback on dynamic system testing such as AUV docking. Typical AUV docking trials are evaluated after recovery and problems can only be interpreted from the vehicle s attempt log. The ability to visually monitor trials of this nature will greatly enhance the post mission analysis and reduce the development time. In addition to ease of scheduling, the OTTB facility will provide wireless surface connectivity with the OTTB infrastructure from anywhere in the deployment area. The underwater OTTB components will be in constant communication with the shore station using a fibre optic network connected through VENUS. Since the OTTB deployment area will be over a kilometre away from the shore station, near the VENUS site, a long range wireless communication system will be installed to provide communications to any surface vessel working in the deployment area. This will allow the deployment crew to be in contact with instrumentation connected to the platform as it is being deployed. In addition, this will allow the surface support team for underwater vehicle operations to track the vehicle s progress in real time and enable low-bandwidth communication with the vehicle through the IAS infrastructure. The platform itself will consist of an aluminium frame with fiberglass decking and hard flotation for trimming. In addition, inflatable surface flotation will turn the structure into a stable work platform once on the surface. The deck will be outfitted with custom mounting arrangements for instrumentation and their associated pressure housings. When the platform is underwater it will be located beneath the buoy of a 3-point mooring. This will allow a small vessel to recover and redeploy the system in a highly controlled manner without requiring the vessel to have dynamic positioning capabilities. This dramatically reduces the cost of the surface support required for routine activities. The platform will also have an integrated sensor package which will provide important feedback about the position and orientation of the platform during recovery and redeployment. This will mitigate problems due to snags, cable twisting, tides and wave action, all of which can make deployments difficult at the best of times and can present serious problems as the sea state increases. The platform sensor package will consist of a pressure housing containing an altimeter with a remote head, a compass, an attitude sensor, and a pressure sensor. A comprehensive sensor interface and monitoring scheme is provided by additional hardware mounted on the platform. The primary component for interfacing static instrumentation is the SIIM. The capabilities of the SIIM are augmented by port adapters and a battery bank. On the outside, the SIIM looks like a large housing with a connection to the VENUS node and eight ports which can connect to instrumentation. On the inside, the SIIM performs two main functions: power management and communications control. At a high level, power management involves reducing the 340 VDC received from the VENUS node to 48 VDC and redistributing the power to the instrument ports. Although the concept is simple, the physical system is much more complex; The VENUS node will provide the OTTB with 1 kw total power, which is only a fraction of the peak power requirements of the OTTB. To circumvent this issue, the power is routed through a battery bank which serves as a buffer and enables the SIIM to provide much higher power at a reduced duty cycle. The battery bank will be a pressure compensated sealed lead acid battery with a custom form factor designed to suit the platforms requirements; provisions will also be made for remote ventilation and maintenance. Therefore, the high voltage from VENUS is first reduced and used to maintain the charge level in the battery bank, and then the voltage from the batteries, which may range between 40 and 56 VDC, is conditioned and supplied at a steady 48 VDC to the instrument port bus. Finally, each port is equipped with 2-stage dead-face switching, voltage and current monitoring, and ground fault detection to ensure the safety of the OTTB and any instrumentation connected to the ports. As an additional feature, one of the eight ports will be a high-power port designed to supply up to 3 kw at 48 VDC for demanding applications such as ROVs, flood lighting, or crawlers. The communication between the shore station and the SIIM will be gigabit Ethernet over single mode fibre; the SIIM will contain a media converter to convert the Ethernet to copper and a high-speed switch to distribute Ethernet to the ports. As a precaution, dead-face switching will also be implemented on the communication lines to provide galvanic isolation. In its standard form a port will provide 48V and an Ethernet connection, but many instrument packages will require something different. To ensure that the SIIM is as flexible as possible in its port configurations, different sensor requirements will be

6 6 handled using port adapters. The port adapters will act as an interface between the SIIM and instruments or experiments that require a different voltage and/or communication protocol than what is provided by the SIIM. A port adaptor will accept 48 VDC and Ethernet from the SIIM and provide 48, 24, 12, or 5 VDC and RS232, RS422, or RS485 to the instrument. The adapters will be comprised of a small pressure housing containing a DC-to-DC converter, associated PCB, and a device server. Using port adapters instead of hardwiring different voltages and protocols into different ports ensures that there are eight usable ports on the SIIM for any potential sensor configuration. Both the power and communication systems will be managed by a remotely programmable controller on the main board. The controller will have reconfigurable telemetry, alarm response, and port control settings. The main board will also be connected to a suite of environmental sensors designed to monitor the health of the SIIM. This sensor suite will consist of a temperature sensor, pressure transducer, leak detectors, and camera for visually inspecting the inside of the pressure housing. B. Integrated Acoustic System (IAS) The concept of an integrated acoustic system (IAS) to provide navigation and communications, in support of science applications, within the ocean's volume is crucially important. Eventually, a series of nested systems are envisioned, from smallscales to regional to basin-scales as required. These networks could service an unlimited number of inexpensive receivers mounted on ROVs, AUVs, or any autonomous instrumentation. The navigation and communications infrastructure would enable vehicles to navigate around the node and ocean bottom, and also through the water column without coming to the surface. They could obtain navigation fixes and communicate their data and status to the users via acoustic modems, and hence through the node, without breaking away from their underwater missions. The IAS components could also provide service to stationary underwater remote instruments, transmitting control data from users, or potentially establishing two-way acoustic communications links in large-scale networks. In combination with underwater vehicles, a full-scale IAS will be a transformational system that leverages many of the scientific programs currently being studied in the underwater engineering community. The smaller IAS which will be established on OTTB will be a first major step in bringing this concept to fruition. The IAS being developed for the OTTB will be designed to provide 4 services: tracking of underwater targets, communication with vehicles and instruments, passive acoustic sensing, and arbitrary acoustic transmission. The tracking system will be capable of monitoring multiple targets simultaneously and be designed with the following specifications: static position accuracy of +/- 10 cm within an arena of one square kilometre and an average depth of 150m. continuous update rate of greater than 1Hz The tracking results will be available in real time through the tracking interface. This will provide users with the ability to track their dynamic experiment throughout the OTTB arena. For vehicle testing, this will provide users with an important baseline of truth data with which to validate the results of their experiments. An off-the-shelf acoustic modem will also be incorporated into the IAS; this will provide facility users with a means of wirelessly communicating with their device using industry standard equipment. This IAS will also be designed with additional sensing and transmission capabilities. This will enable expansion and further acoustic research; the specifications for these capabilities are as follows: The ability to passively receive and log continuous acoustic data. The ability to transmit an arbitrary signal from 10 to 80kHz The IAS, depicted in Fig. 4, consists of an acoustic SIIM, a series of sub-sea satellites, and an acoustic modem. The acoustic SIIM is a connection point for the infrastructure related to the IAS. This SIIM acts as a central hub providing precision timing to each satellite as well as 100BASE-FX Ethernet and power at 300VDC. When tracking targets, the acoustic SIIM calculates the time of flight from a target transmitter to each of the satellites in the IAS network. In this configuration, the target transmitter can be a small self contained pinger, which can be easily mounted to the hull of a vehicle. In addition to being a central hub for the connection to each of the satellites, the acoustic SIIM is also a connection point for the acoustic modem. The modem will be similar in capabilities to a Benthos ATM-885 medium frequency acoustic modem. This modem will provide low bandwidth wireless communication to AUVs and stand alone instrumentation not directly connected to the cabled infrastructure. The IAS satellites each have a series of acoustic elements used to project acoustic signals into the water and receive acoustic signals from the water. Each satellite consist of a series of hydrophones that can monitor acoustic signals in the frequency band from 5 to 100kHz and an acoustic projector able to transmit arbitrary acoustic signals in the frequency band from 10 to 80kHz. The satellites contain the drive electronics for the projectors as well as variable-gain low-noise amplifiers and analog to digital converts for each of the hydrophones. Real time processing of the received acoustic signals is performed in each satellite before being transmitted back to the acoustic SIIM. As well as the acoustic hardware, each satellite will have a sensor suite to ensure the accuracy of the signal analysis. This suite will include a high accuracy quartz pressure transducer, biaxial tilt sensor, and temperature sensor.

7 7 IAS Satellite IAS Satellite EO Cable (800m) EO Cable (800m) Acoustic SIIM (A-SIIM) Acoustic Modem To VENUS OTTB Platform EO Cable (1000m) IAS Satellite 1000 meters EO Cable (800m) EO Cable (800m) IAS Satellite IAS Satellite C. User Interface 1000 meters Fig. 4 Integrated Acoustic System Architecture Three levels of user interface will be implemented on the OTTB. Users will be able to access the system from anywhere in the world and interact with their instruments as if it were on their work bench. The three levels of access are as follows: Static User Interface for interacting with and monitoring instruments attached to the SIIM Dynamic User Interface for interacting with and monitoring dynamic objects using the 3D tracking system Facility management interface (internal use only) The static user interface will be available remotely through controlled access and will allow users to access their own software and interact with their instrumentation as if it were locally attached, and the dynamic user interface is an application which is available to those users wishing to use the OTTB tracking system to monitor their experiment. The facility management interface will only be accessible locally on the OTTB intranet, and will provide complete access to all the system components. 1) Static User Interface The static user interface will be the baseline user interface; one of the key requirements is that users can interact with their instruments using their own software without any major configuration changes. To enable this, each instrument attached to the OTTB will be on its own virtual LAN. This will isolate the instruments on each port and provide a means of regulating access by users to ensure they only see their own instrument. The user will be provided with an account for accessing the system, which will allow them to access their instrument as if it were locally connected. Once logged in, serial port emulation software or simple tunnelling will allow the user to emulate their normal connection and use their own software to control and monitor their instrument. This will be an especially important feature for companies using the OTTB system to conduct live demonstrations of their instrument and their software interface for potential clients. As an additional feature, the OTTB interface will have the capacity to log Ethernet traffic from an instrument, providing a means of logging data for sensors that do not have internal logging capabilities. 2) Dynamic User Interface The dynamic user interface will extend the capabilities of the static user interface by providing an application for interfacing with the real-time tracking system. The tracking interface will be an application which will provide controlled access to the tracking data produced by the IAS. This application will not only provide a means for collecting tracking data but will also provide a 3D graphical representation of the OTTB arena with integrated visual tracking information. This will provide a near real-time visual monitoring system for users to monitor the progress of their dynamic experiments. All control of the users experiment will be done using their software as with the static user interface, the tracking application will only provide passive monitoring. The advantage of this configuration is that anyone with proper access can watch a dynamic mission in real time: for example, a company executive can keep an eye on the testing, or for more developed products, a sales manager could set up real-

8 8 time viewings for important clients. 3) Facility Interface The facility interface will be an omnipotent control and monitoring system. It will provide real-time monitoring and control for all the infrastructure components including the IAS, video system, and SIIM including independent monitoring and control capabilities for each of the ports. This allows a static instrument to be monitored based on its power consumption and expected communication frequency, and if the instrument starts to malfunction it can be shut off at the port prior to jeopardizing the platform. The tracking interface will also be part of the facility interface and will permit the facility managers to monitor all of the activities in the arena and ensure that vehicles stay in the designated safe zones. III. THE PROPOSED RESEARCH AT THE FACILITY The OTTB project will focus on providing research and development services to two primary sectors: Underwater engineering research including the development of innovative ocean technologies, such as: underwater vehicles; high definition imaging systems; integrated acoustic system for underwater navigation and communication. Interdisciplinary Marine science provide a facility for marine scientists to design and test unique instrumentation, particularly for application on cabled ocean observatories. The OTTB project will utilize current VENUS science projects as a guide in the development; these include experiments in the areas of studies of sponge reefs, active seismic regions, a delta dynamics laboratory and acoustics for cetacean monitoring. Once the facility is operational, it will be put to use by researchers at the University of Victoria s Ocean Technology Lab (OTL). The primary research objectives of the OTL are described in the sections below. A. Underwater Vehicle Research Long-term Tethered Deployments One of the long-term requirements for cabled ocean observatories is for a multi-purpose underwater vehicle that can be tethered to a node for extended periods. A tethered vehicle has the advantage of real-time high-speed communication which can transmit video and other telemetry back to the surface support while out on a mission. With the OTTB, it will be possible to integrate a tethered vehicle into the VENUS observatory system and facilitate research into several of the lagging technological areas including underwater docking. This vehicle research will be enhanced by a complete integration with the IAS, which will act as a positioning system and provide real-time feedback for guidance, navigation and control testing. A tethered vehicle should be capable of remaining attached to an observatory node for long durations; the vehicle could perform multiple functions: carry science packages in the vicinity of the node; re-position autonomous instrument packages; gather high resolution imagery of sea-floor specimens on scheduled timelines; collect sea-floor samples and deliver to sensors for analysis; undertake service and repair tasks on sea-floor equipment. The vehicle will be operated over the Internet through the VENUS system, ensuring compatibility with other observatory locations. Ultimately, this will be an extremely powerful, multitasking system that will leverage the many aspects of the node. Therefore, the research, development and implementation of a tethered vehicle will be undertaken. Initial examination of the problem indicates that the following issues need to be addressed through the evaluation of analytical models and prototypes on the OTTB: Tether management system (TMS) The vehicle and TMS will be fully integrated with a control system distributed between the TMS, vehicle propulsion and control, and operator. The tether will be long enough for the vehicle to surface (Saanich Inlet) making it an excellent test bed tool to support other research. Integrated Control and Navigation System Integrate the vehicle control system with the acoustic position tracking system of the IAS. Long-term research topics are to upgrade the vehicle control technique for operation with the IAS; investigate integration of seafloor topography data and video imagery with vehicle control; and, vehicle guidance and teleoperation at distances of up to several hundred meters around the node employing the integrated acoustics system, video camera, vehicle sensor data and Ethernet link. B. Underwater Vehicle Research Hybrid Autonomous Vehicle The success of many planned science programs, in the coming years, relies heavily on the ability to sample at significant distances from an observatory and at many points in the water column. For example, chemical, biological and acoustic data monitored on a regular basis at kilometre distances and profiling between the surface layer (0 to 200 m deep) and the sea bottom. The scientific possibilities made possible by this remote monitoring technology are enormous. A hybrid autonomous underwater vehicle is special kind of AUV which is hydrodynamically efficient, for long distance travel, and can manoeuvre at zero velocity, to interact with the local environment [5]. The hybrid vehicle design concept transforms the capabilities from a simple vehicle to a comprehensive, scientific sensing platform. While working toward this eventual goal, the OTTB project will adopt a step-wise approach and will focus, in the later stages, on critical technical challenges facing hybrid vehicle implementation. The OTTB design will include sensors and hardware that

9 9 will allow targeted research on: Automated docking of a hybrid vehicle to an observatory node using multiple sensor inputs. Short range (several meters) and long range (kilometres) communication with an autonomous vehicle. Guidance and control of an autonomous vehicle using the IAS. Charging of vehicle batteries employing inductive coupling or other means (while docked). A first prototype vehicle that is suitable for performing many of these early stage research initiatives is shown in the photograph of Fig. 2. The vehicle is ideal for exploring the integrated acoustics navigation, automated docking and acoustic communications. C. Autonomous Instrumentation An autonomous instrument is part of an instrumentation system which provides communication through the use of an autonomous or tethered underwater vehicle. The instrument package contains a homing beacon and a low power communication system. Then the underwater vehicle can home in on the instrument and, once in range, initiate a communication link. This link could be used to download data, upload new software, or collect vital statistics such as battery levels. An autonomous instrument can be deployed at any location on the seafloor that is accessible by an underwater service vehicle. When used in the context of an ocean observatory which has an underwater vehicle permanently on-site, autonomous instruments can extend the reach of the node without requiring additional cables or a power hungry wireless networking system. Autonomous instrument interfaces can also provide additional flexibility to existing underwater sensing systems. Since the service vehicle only passively interacts with the sensor, it can be used to obtain interim data during an experiment without disturbing the sensor mooring. This can provide invaluable information about the status of long term experiments and provide interim data to researchers. This type of data collection and monitoring system could reduce the cost of doing research by making permanently installed research moorings more useful. D. Integrated Acoustic System Research An integrated acoustic system (IAS) providing navigation and communications, in support of science applications, within the ocean's volume is crucially important. The navigation function is analogous to the satellite-based Global Positioning System (GPS), but here implemented underwater employing acoustics. Eventually, a series of nested systems are envisioned, from local to regional to basin-scale as required. However, in this project a small number of acoustic satellites receiving coded, low power signals will service inexpensive pingers mounted on the tethered ROV, hybrid AUV and any autonomous instruments to provide high precision tracking information. These satellites can serve double duty by transmitting control data from users to remote instruments, and two-way acoustic communications links in large-scale networks can be established. Acoustic based instrumentation that shares the acoustic bandwidth with, and depends upon, the navigation and communications capabilities completes the concept of integrated acoustic systems. This navigation and communications infrastructure will enable the ROV and AUV to navigate around the node and ocean bottom, and also through the water column without coming to the surface. They can obtain navigation fixes and communicate their data and status to the users via acoustic modems, and hence through the node, without breaking away from their underwater missions. Combined with underwater vehicles, this is a transformational system that leverages many of the scientific programs described elsewhere in this application and in the wider research community. Implementation on the OTTB will be a first major step in bringing this concept to fruition. The following is a list of some of the research that the IAS will enable: An integrated communications and 3-D navigation system covering several km in the horizontal plane and the bulk of the water column in the vertical. A communications channel for command/control and relatively low volume data return with suitable acoustic spectrum management. Direct position data for bottom mounted (locally tethered ROV) and free-swimming sensor platforms (AUV). A sensing platform for acoustic tomography and passive applications (tracking marine mammals, earthquake detection, etc.) IV. DEVELOPMENT TIMELINE The OTTB will be a phased extension to the VENUS node, with the major engineering research focus being the continued development of underwater vehicle technology, appropriate for the cabled observatory environment, and the implementation of an acoustic positioning system. The major science focus will be the integration and application of the technologies with selected science programs planned for VENUS and NEPTUNE Canada. The project is projected to commence in October 2007 and will have a design and construction phase continuing through to the end of This will be followed by a system-commissioning phase that will last for one year and lead into full scale operation. The timeline and deliverables at the end of each year will be:

10 10 Year 1: The OTTB top-side ROV and the recoverable platform which includes the mooring, SIIM, camera system and user interface for accessing attached instrumentation. Year 2: The IAS will be deployed with an operational tracking system, and the hybrid AUV and integrated docking system design phase will be complete. Year 3: The final year will focus on construction and deployment of the hybrid AUV followed by operational testing and integration with the docking system. Advances in the materials and systems aspects of the overall OTTB will be accomplished over the entirety of the 3-year program. V. CONCLUSION The OTTB project is a comprehensive plan to develop these innovative ocean technologies, systems engineering methodologies and new ways of performing science coupled to the underwater observatory concept. This innovative laboratory will provide important research opportunities to scientists and engineers and is a necessary research platform from which the role of ROVs, AUVs, and integrated acoustics, in ocean science, can be further explored. The application of the technology by the science community will undoubtedly result in modifications, improvements and radically new concepts to performing research on VENUS and NEPTUNE. For example, it is anticipated that a more ambitious underwater vehicle development program will be required to meet the needs of the planned deep water sites on NEPTUNE Canada. The goal of the OTTB project is to ensure that underwater engineering research keeps pace with demand and that researchers on the west coast have a state-of-the-art facility to assist them in attaining their objectives. REFERENCES [1] C. R. Barnes, M. M. R. Best, B. D. Bornhold, S. K. Juniper, B. Pirenne, and P. Phibbs, The neptune project - a cabled ocean observatory in the NE Pacific: Overview, challenges and scientific objectives for the installation and operation of Stage I in Canadian waters, in Symposium on Underwater Technology and Workshop on Scientific Use of Submarine Cables and Related Technologies, 2007, Aug. 2007, pp [2] P. Fairly, Neptune rising [undersea observatory], IEEE Spectrum, vol. 42, no. 11, pp , Nov [3] J. Kennedy, E. Gamroth, C. Bradley, and A. A. Proctor, Decoupled modelling and controller design for the hybrid autonomous underwater vehicle: MACO, International Journal of the Society for Underwater Technology, vol. 27, pp , [4] C. Posey, Robots of the deep blue yonder, Popular Science, February [5] R. L. Wernli, AUV commercialization-who s leading the pack? in IEEE OCEANS, vol. 1, Sept , pp