Abstract:
The present invention is a device and method of transferring data from an autonomous underwater vehicle to a control center located above. The system comprises a plurality of canisters designed to store a packets of data and transport that data to the surface where the system transmits the data to a control center receiver. A compressed lifting gas released into a balloon provides buoyancy to transport the canister from depth to surface. At the surface the balloon lifts an antenna to a sufficient altitude for reliable communication. After transmission of the data, the device releases the balloon and sinks to the sea floor.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS  
       [0001]    This application claims the benefit of U.S. Provisional Application No. 60/376,701, filed Apr. 30, 2002. 
     
    
     
       STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT  
         [0002]    Not Applicable.  
         BACKGROUND OF THE INVENTION  
         [0003]    1. Field of the Invention  
           [0004]    The invention relates to an apparatus and method of transferring mid-mission data from autonomous deep-sea exploration and inspection devices to a control center using releasable information communication canisters.  
           [0005]    2. Description of the Related Art  
           [0006]    The use of autonomous vehicles is widely known in the field of underwater exploration and inspection. Autonomous units are used to study the ocean floor, currents and life forms. Commercial applications include exploration for a variety of minerals, to include diamonds, oil and gas. Autonomous vehicles are used to inspect and repair underwater pipelines, communication systems and other underwater equipment. Other applications include military minesweeping and hazardous rescue, recovery and salvage operations.  
           [0007]    During a subsurface mission, an autonomous underwater vehicle collects data pertinent to the particular mission, whether the data concerns water temperatures or the integrity of a petroleum pipeline. The information is either immediately sent to a control station or stored in onboard electronic memory. Water is a poor medium for communication, except over short distances. If an operator urgently needs the information, a communication wire or fiber optic cable must be connected to the vehicle, either permanently with a tether or through providing a subsurface docking station module. Otherwise the data is recovered when the vehicle surfaces.  
           [0008]    An alternative exploration means is to tow a remotely operated vehicle behind a support vessel. The tow cable and control lines can incorporate a communication line for data recovery. Though this method provides real-time, high-resolution data and works well at relatively shallow depths, operations at deep depth requires long lengths of cable that quickly become a substantial challenge to manage.  
           [0009]    A self-propelled vehicle having just a communication and control tether is able to reduce the bulky cable connection between the exploration vehicle and the control vehicle, but this system reaches its limitations in deep-sea operations. In an article titled,  Autonomous Underwater Vehicles , James G. Bellingham, Principal Research Engineer at MIT&#39;s Autonomous Underwater Vehicles Laboratory, published in  The Global ABYSS: An Assessment of Deep Submergence Science in the United States , University-National Oceanographic Laboratory System, Deep Submergence Science Committee, in 1994, discloses that at depths exceeding 1000 meters the tether of a remotely operated vehicle dominates operational considerations. The article focuses on the advantages and prospects for use of autonomous vehicles, which at the time were rated to operate to depths of 6000 meters.  
           [0010]    If it is not possible to maintain real-time communication with the autonomous vehicle, receiving frequent transfers of the recently obtained data is the next best alternative. In many situations the information being gathered by the vehicle is critical. If a device conducting an inspection of a pipeline detects a leak or other significant event, the cumulative delay for the completion of the mission, recovery of the vehicle, and analysis of the data, allow the effects of the problem to increase. Trimming the delay by even a couple hours is valuable.  
           [0011]    Current systems employ docking stations, which are deployed by a cable to the operational depth of the vehicle. The vehicle is programmed to dock with a docking module when one is available during a mission. Once docked, communication is established through the docking interface and the data is transferred over the module cable. Disadvantages of such systems include the cost of locating a docking module in the vehicles mission field and the fixed nature of the docking station. In addition to the cost of the subsurface module and connecting cable, a support platform must be placed on location for the duration of module deployment, interfacing, and recovery.  
           [0012]    Examples of prior art exploration systems, which take advantage of autonomous vehicles, follow:  
           [0013]    U.S. Pat. No. 5,687,137 issued to Schmidt et al. on Nov. 11, 1997 discloses an apparatus and method of conducting oceanographic sampling using an array of vertical, stationary analysis buoys, which, by means of wireless modem, communicate with a control station and direct the operation of at least one underwater analysis vehicle, such vehicle having the capacity to collect and store data and optionally dock to a stationary buoy in order to transfer data to the control station and rated to a depth of 6700 meters.  
           [0014]    U.S. Pat. No. 5,995,882 issued to Patterson et al. on Nov. 30, 1999 discloses an autonomous underwater vehicle system for ocean science measurement and reconnaissance, said vehicle possessing the capacity to collect and store data, as well as a global positioning system receiver, a radio transceiver and strobe electronics to determine and communicate location for recovery once the vehicle returns to the surface.  
           [0015]    U.S. Pat. No. 6,167,831 B1 issued to Watt et al. on Jan. 2, 2001 discloses an autonomous underwater vehicle for performing subsurface operations comprised of a primary vehicle with a tethered, free-moving craft, such that the primary vehicle delivers the craft to an employment location where the deployed tethered craft performs work. A subsurface docking module is deployed to allow the primary vehicle to dock adjacent to the work site and receive communication and auxiliary power.  
           [0016]    It would be an improvement to the art to provide a system for periodic transfers of discrete quantities of recently obtained data from a deep-sea autonomous underwater vehicle to a control center. Such periodic transfer of data would allow mission modification and/or permit timely response action to the data. It would be a further improvement for the system to not require support vehicles above the mission field except for deployment and recovery. Such a system must accomplish these improvements while using minimal power from the vehicle system and maintaining the vehicle&#39;s buoyancy characteristic.  
         BRIEF SUMMARY OF THE INVENTION  
         [0017]    Accordingly, the objects of my invention are to provide, inter alia, a data transfer system from a deep-sea data collection device that:  
           [0018]    provides mid-mission transfer of packets of data from a collection device to a control center, thereby allowing analysis of the data during the mission and decreasing the time from data collection to use of the information;  
           [0019]    provides the capacity to transfer a quantity of collected data in a single packet;  
           [0020]    eliminates the urgency of immediate recovery of the vehicle upon completion of the mission thereby avoiding possible hazardous recovery conditions;  
           [0021]    reduces or eliminates the need to have a surface support team;  
           [0022]    eliminates the need for the vehicle to surface during its mission;  
           [0023]    preserves the buoyancy characteristics of the vehicle to which it is attached;  
           [0024]    preserves the collection vehicle&#39;s power supply;  
           [0025]    transmits at some distance from the vehicle, preserving the secrecy of the vehicle&#39;s location; and  
           [0026]    is self-scuttling upon transmission completion in order to avoid third-party retrieval.  
           [0027]    Other objects of my invention will become evident throughout the reading of this application.  
           [0028]    My invention is an apparatus and system for receiving packets of data from an underwater data collection system and transferring such packets of data via a disposable, self-contained canister. Each canister, upon receiving a data packet, is transported to the surface by a balloon deployed from the canister by a small buoyant gas generator. The balloon is tethered to the canister by a wire that may act as an antenna upon reaching the surface. Once the antenna clears the surface wave action a transponder in the device establishes contact and relays the packet of data to a control center. After transfer is complete, the buoyancy of the balloon is released and the entire canister sinks. The canisters may be loaded in a reusable pallet that secures to the vehicle. The pallet houses a communication link from the control unit on the vehicle to each canister. The entire system, including the pallet and the canister (until release) are constructed to be neutrally buoyant at depth (displacing a volume equal to its weight in water), so that they do not disturb the buoyancy profile of a particular underwater vehicle. The pallet is shaped to minimize drag when mounted to the underwater vehicle. 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0029]    [0029]FIG. 1 is a cut-away side view of a canister in a stowed configuration.  
         [0030]    [0030]FIG. 1A is a partial cross-sectional side view of a frangible pin retaining a canister cover to a canister in a stowed configuration.  
         [0031]    [0031]FIG. 1B is an exploded view of the frangible pin connection of FIG. 1A.  
         [0032]    [0032]FIG. 2 is a cut-away bottom view of a canister.  
         [0033]    [0033]FIG. 3 is a block diagram depicting the components interfacing the canister processor.  
         [0034]    [0034]FIG. 4 is a schematic side view of an autonomous underwater vehicle equipped with a pallet.  
         [0035]    [0035]FIG. 5 is a schematic top view of a pallet without canisters.  
         [0036]    [0036]FIG. 6 is a partially cut-away side view of a pallet housing canisters.  
         [0037]    [0037]FIG. 7 is a schematic side view of a deployed canister.  
         [0038]    [0038]FIG. 8 is a flow diagram depicting the processor control sequence.  
     
    
     DESCRIPTION OF THE INVENTION  
       [0039]    [0039]FIGS. 1 and 2 depict an exemplary data transfer canister  20  of the present invention. Within canister housing  22  is data storage module  32 , electronics module  30 , lifting gas container  46 , balloon  40 , tether  43  and power supply  50 . Canister housing  22  has a shaped in order to withstand the extreme pressures of great depths. In the exemplary embodiment canister housing  22  has a cylindrical shape. Canister top  24  is shaped to reduce drag when moving through the water. In the exemplary embodiment canister top  24  has a dome shape. Data connectors  34 , connected to data storage module  32  inside canister housing  22 , penetrate canister housing  22  in a pressure and water resistant manner. In the exemplary embodiment data connectors  34  are formed into canister housing base  21  of canister housing  22 .  
         [0040]    Referring to FIGS. 1, 1A,  1 B and  2 , in a stowed configuration, canister top  24  of canister  20  is connected to the entire perimeter of canister housing side  23  at top connection  79 . In the preferred embodiment, groove  74  runs around the entire bottom edge  72 , intermediate top outer wall  76  and top inner wall  78  of canister top  24 . Raised tongue  84  extends outwardly from the entire top edge  82  of canister housing side  23 , intermediate housing outer wall  86  and housing inner wall  88 . Groove  74  and tongue  84  are correspondingly shaped to provide a close, slidable fit.  
         [0041]    Canister top  24  has a number of canister top holes  70  adjacent to bottom edge  72 , passing from outer wall  76  to inner wall  78  through groove  74 . Canister housing side  23  has corresponding canister housing holes  80  in raised tongue  84 , passing from tongue outer wall  85  to tongue inner wall  87 . Frangible pins  26  are shaped and sized to fit in the junction of canister top holes  70  and canister housing holes  80 , securing canister top  24  to canister housing side  23 . Each frangible pin  26  has weakening score  27 , which promotes frangible pins  26  breaking when separating pressure is applied to top connection  79  of groove  74  and tongue  84 .  
         [0042]    Referring to FIGS. 1 and 1A, balloon  40  may be positioned tightly against canister top  24 . Balloon  40  lays flat across the inside of top connection  79  acting as a waterproof membrane that supports the waterproof seal of top connection  79 . Balloon  40  may be folded into canister  20  in a manner that allows initial balloon  40  expansion from the area around balloon release valve  41 . Integral to balloon  40  may be antenna  42 . Balloon  40  and antenna  42  are both connected to canister  20  by tether  43 . Tether  43  may be a communication enabling wire  44  operatively connected to electronics module  30 , which may have antenna  42  and transmitter/receiver  36 .  
         [0043]    Referring to FIG. 1, directly under balloon  40  in canister housing  22  may be tether  43 . In the exemplary embodiment tether  43  is wound in order to minimize the volume tether  43  collectively occupies and to provide uniform support against balloon  40  as deep-sea pressures compress against canister  20 . Tether retainer  45  clamps to tether  43  in order to keep the bulk of tether  43  in container  20  until container reaches the water surface.  
         [0044]    Beneath tether  43  is lifting gas container  46 . Lifting gas container  46  is securely anchored to inner wall  88  of canister housing side  23 . Gas valve  49  connects gas fill line  48  to lifting gas container  46 . The other end of gas fill line  48  connects to balloon  40  at balloon release valve  41 . In the exemplary embodiment lifting gas container  46  is a pressure vessel and lifting gas  47  is helium, pressurized sufficiently to overcome ambient pressures at operating depth. Other gasses, stored and delivered in various methods, can be used without deviating from the invention.  
         [0045]    Referring to FIGS. 1 and 2, beneath lifting gas container  46  is waterproof partition  28 . Waterproof partition  28  seals to the perimeter of canister housing side  23 . Control wiring  60  passes through waterproof partition  28  connecting electronics module  30  to balloon release valve  41 , tether retainer  45 , gas valve  49  and depth sensor  68 .  
         [0046]    In the exemplary embodiment, beneath waterproof partition  28  are an electronics module  30 , data storage module  32  and power supply  50 . Exemplary power supply  50  is positioned around the periphery of the interior of canister housing side  23 . In this manner power supply  50  allows room for the other components. In the exemplary embodiment, power supply  50  comprises multiple batteries resting on canister housing base  21  and against canister housing side  23 . In the exemplary embodiment, twenty AA batteries provide sufficient energy for canister  20  to complete a data transfer mission. Twenty-three batteries are depicted in the exemplary embodiment to ensure energy requirements are met. Power supply  50  can be other independent energy sources without deviating from the invention.  
         [0047]    Data storage module  32  provides a stable storage medium for data transferred to canister  20 . In the exemplary embodiment, data storage module  32  is a compact four-gigabyte harddrive, positioned against canister housing base  21 . Other types of data storage mediums can be used for data storage module  32 .  
         [0048]    Referring to FIGS. 1, 2 and  3 , electronics module  30  is positioned adjacent to data storage module  32  in order to minimize connection distance, and may be a circuit card. Electronics module  30  may comprise processor  38 , transmitter/receiver  36 , lifting gas control  62 , tether deployment control  64  and scuttling control  66 .  
         [0049]    Processor  38  controls the operation of canister  20 . Processor  38  is wired to data storage module  32  in order to both send and receive instructional and data signals. Processor  38  is also wired to transmitter/receiver  36  to both send and receive instructional and data signals. Processor  38  is wired to send instructional signals to lifting gas control  62 , tether deployment control  64  and scuttling control  66 .  
         [0050]    Lifting gas control  62  initiates releasing lifting gas  47  into balloon  40 , through gas fill line  48 . In the exemplary embodiment lifting gas control  62  opens gas valve  49 , attached as the interface between lifting gas container  46  and gas fill line  48 .  
         [0051]    Depth sensor  68  detects when canister  20  reaches the water surface. In the exemplary embodiment, depth sensor  68  is a pressure sensor set to detect one atmosphere of pressure, or the pressure at sea level.  
         [0052]    Tether deployment control  64  initiates releasing the entire length of tether  43 , which secures balloon  40  to canister housing  22 . In the exemplary embodiment tether deployment control  64  releases tether retainer  45 , which is secured to lifting gas container  46 . Tether retainer  45  keeps the bulk of tether  43  within canister housing  22  until canister  20  reaches the water surface.  
         [0053]    Scuttling control  66  initiates a signal to the tether retainer  45  to cut tether  43 , breaking the connection of balloon  40  and canister housing  22 . In that canister  20  is negatively buoyant without inflated balloon  40 , canister  20  sinks to the bottom. Scuttling control  66  can be deactivated if canister recover is desired.  
         [0054]    Referring to FIGS. 1, 4 and  5 , canisters  20  are attached to the top of underwater vehicle  100  mounted to pallet  10 . Pallet  10  is shaped to minimize drag on vehicle  100 .  
         [0055]    Pallet  10  releasably holds canisters  20  in canister wells  12 , with data connectors  34  in place against canister contacts  18 . Canister contacts  18  are connected to pallet control unit  14  through wiring harness  16 . Control unit  14  connects to vehicle processing unit  102  through the coupling of vehicle transfer wire  104  and pallet transfer connection  106 . Vehicle processing unit  102  is a processing unit of the autonomous underwater vehicle  100 , which has been programmed to transfer a copy of data collected over a period of time. Pallet  10  may be reusable by reloading canister wells  12  with other stowed canisters  20 .  
         [0056]    Referring to FIGS. 1, 2,  3  and  7 , each processor  38 , lifting gas control  62 , tether deployment control  64 , and scuttling control  66 , of electronic module  30 , and data storage module  32  operate off the individual power supply  50  in each individual canister. Each processor  38  controls the sequential activity of that one canister  20  during operation.  
         [0057]    Referring to FIGS. 1 through 7, when the programming of vehicle processing unit  102  identifies that the allotted time has passed or the allotted quantity of data has been collected, vehicle processing unit  102  attempts to transfer a copy of that data as a packet to the next canister  20  in pallet  10 . The data signal is sent over transfer wire  104  to transfer connection  106  to pallet control unit  14 . Control unit  14  routes the signal to the next canister  20  in sequence. In the exemplary embodiment, control unit  14  is a passive router that uses the energy of the transfer signal, thereby minimizing energy use. Detecting ( 71 ) a transfer signal from vehicle processing unit  102  initiates processor control sequence  70  in that particular canister  20 .  
         [0058]    The steps of processor control sequence  70  are as follows. Detecting ( 71 ) data transfer from vehicle processing unit  102 . Receiving ( 72 ) the data from vehicle processing unit  102  and storing in data storage module  32 . Initiating ( 73 ) release of lifting gas  47  into balloon  40 , causing canister  20  to become buoyant and release from pallet  10 , leaving canister well  12 . Detecting ( 74 ) surface with signal from pressure sensor  68 . Extending ( 75 ) balloon  40  on the full length of tether  43  by releasing tether retainer  45 . Establishing ( 76 ) communications link with control receiver  200  by transmitter/receiver  36  transmitting a “lock-on” signal until control receiver  200  acknowledges. Sending ( 77 ) data contained in data storage module  32  by transmitter/receiver  36 , through wire  44  and antenna  42 . Initiating ( 78 ) scuttling, which completely releases tether retainer  45 , disengaging tether  43  from balloon  40 .  
         [0059]    In order to control the use of energy, electronics module  30  may not activated until processing unit  102  completes sending data to canister  20 .  
         [0060]    Once balloon  40  sufficiently expands, frangible pins  26  holding top  24  to walls  22  break and the volume of balloon  40  may expand beyond boundaries of canister  20 . As balloon  40  expands, the positive buoyancy increases, accelerating canister  20  towards the surface. Balloon  40  separates a distance from canister  20 , attached to tether  43 . Tether retainer  45  may prevent deployment of the entire length of tether  43 . Enough tether  43  is freed to provide a distance sufficient to prevent inadvertent contact between balloon  40  and canister  20  that could damage balloon  40 . The bulk of tether  43  is secured within canister  20  by tether retainer  45 , which in the exemplary embodiment is secured to lifting gas container  46 .  
         [0061]    Once canister  20  is at the surface and tether retainer  45  releases the bulk of tether  43 , balloon  40  ascends to an altitude of the full length of tether  43 . In the exemplary embodiment that height is 100 feet (˜30.5 m). Antenna  42  on balloon  40  is above wave action and has a clear transmission path to control receiver  200  for a control center (not shown). In the exemplary embodiment transmitter/receiver  36  operates on ultrahigh frequency (UHF), which is compatible with ground or satellite operation.  
         [0062]    Alternately, canister  20  can be programmed to receive signals to retransmit data or to the data from data storage module  32 . An alternate embodiment (not shown) of scuttling control  66  initiates a charge (not shown), destroying the data on data storage module  32 . Other scuttling devices and techniques can be used, separately or in combinations.  
         [0063]    Various alternate embodiments may be arranged for the disclosed components of canister  20 . In an alternate exemplary embodiment (not shown), lifting gas container  46 , gas valve  49  and part of gas fill line  48  is housed on pallet  10 . Gas fill line  48  operatively connects to each balloon  40  on each canister  20 . In this configuration, a part of gas fill line  48  contained in canister  20  may have a one-way flow valve, to permit lifting gas to enter balloon  40 . In this embodiment, gas valve  49  may be controlled by vehicle processing unit  102  to sequentially supply a quantity of lifting gas to a particular canister  20  during the initiating ( 73 ) release step of each particular canister  20 .  
         [0064]    In an alternate exemplary embodiment, electronics module  30  and data storage module  32  may be of sufficiently little weight so as to be integrated into balloon  40 . In this embodiment, balloon  40  may serve as water-proof section, protecting electronics module  30  and data storage module  32  from the sea elements.  
         [0065]    Currently, a four-gigabyte harddrive meets the anticipated requirements for data storage module  32  for the operation of canister  20 , in order to transfer one hour of data. The harddrive storage technology may include any variety of storage medium to include, but not be limited to magnetic or optical surface mediums, or flash memory mediums. It is anticipated that technological advancements will increase the options and capabilities of data storage module  32 , as well as data collection. These advancements in data handling technology are anticipated and are within the scope of this invention. The exemplary embodiment is designed to transfer data packets in one-hour increments. Depending on the length of a vehicle  100  mission, these increments can be increased or decreased. Additionally, pallet  10  can be adapted to mount on the sides or bottom of vehicle  100 .  
         [0066]    The foregoing disclosure and description of the invention is illustrative and explanatory thereof. Various changes in the details of the illustrated construction may be made within the scope of the appended claims without departing from the spirit of the invention. The present invention should only be limited by the following claims and their legal equivalents.