Abstract:
A payload launch system that uses an inflatable air bag ram to launch a payload, such as an unmanned aerial vehicle, from a launch chamber of a launch tube. The air bag ram seals with the interior surface of the launch tube to isolate a dump valve that controls the flow of compressed gas from a gas storage chamber into the air bag ram. The air bag ram sealing with the interior surface of the launch tube isolates the dump valve, both pre-launch and post-launch, from any water or debris carried in with water in which the payload launch system is disposed

Description:
FIELD 
       [0001]    This disclosure relates to launching payloads including, but not limited to, unmanned aerial vehicles (UAV). 
       BACKGROUND 
       [0002]    UAVs continue to increase in capability and applications. Transporting and launching small, fragile UAVs can be tedious and time consuming to setup and launch in certain environments. Transport, setup and launch can be extremely challenging in remote covert locations or from a moving platform. 
         [0003]    UAVs need to be transported without damaging their fragile structures and time is needed to prepare for flight and launch. Launching UAVs becomes difficult when launching from remote covert locations in harsh environments. Also, UAV&#39;s and existing rail type launch systems are not designed to handle prolonged prelaunch exposure in harsh environments. Launching a UAV from a covert underwater platform, moving or not moving, is one example of a harsh environment. 
         [0004]    Mobile land vehicles operating in the harsh environments do not currently carry rapid, ready to launch UAV systems or utilize them as a forward scout that are instantly deployed from inside their vehicles. This becomes a particular problem in urban environments where snipers or RPGs await in ambush on roof tops. 
         [0005]    Autonomous boats patrolling the perimeter of an anchored ship currently have no method to put a UAV in the air to extend an aerial eye beyond the perimeter and on inbound traffic. 
         [0006]    Currently UAVs are launched from moving and fixed platforms. Small UAVs can be launched by hand. The launchers used for moving and fixed platforms are mostly rail type catapults that take time to setup, while the rail and UAV are fully exposed to the environment. Hand launching needs a man to physically throw the small UAV into the air, which might not be an option under fire or in a rapidly moving vehicle. There are specialty launchers specifically designed to launch UAVs from underwater but they cannot be used universally for any other application. 
         [0007]    In addition, as demand for remote autonomous operations increases, it becomes difficult and expensive to deliver UAVs to a final covert launch position. The endurance of small UAVs is limited by the battery supply they can carry. Further, current launch techniques of UAVs is typically either a manned operation or requires set-up of a rail type launch system. In the case of manned UAV launch, operators position themselves at the final launch point and release the UAV. This creates a situation of putting humans in harm&#39;s way and potentially losing the advantage of surprise. 
       SUMMARY 
       [0008]    A payload launch system is described that uses an inflatable air bag ram to launch a payload from a launch chamber of a launch tube. The launch tube can be used to transport and protect the payload from harsh environments for extended periods prior to launch. The payload can be any unmanned payload that one may wish to transport and launch, and protect the payload from harsh environments for extended periods of time prior to launch. In one embodiment, the payload can be a UAV. In one embodiment, the launch system is used to launch the payload from a marine environment that can be saltwater, freshwater, or brackish water. In one embodiment, the payload launch system is designed to float in water at the surface thereof and launch the payload from the water surface. 
         [0009]    The air bag ram seals with the interior surface of the launch tube defining the launch chamber to isolate a dump valve that controls the flow of compressed gas from a gas storage chamber into the air bag ram. The air bag ram sealing with the interior surface of the launch tube isolates the dump valve, both pre-launch and post-launch, from any water or debris carried in with water in which the payload launch system is disposed. 
         [0010]    As used herein, a UAV can be any unmanned aerial vehicle designed to fly or float in the air. In one specific embodiment, the UAV can be a folding version sized to fit within the launch tube, with spring loaded, foldable airfoils and a battery powered propulsion system such as a propeller. The term “unmanned” used herein means the payload, such as the UAV, does not physically carry a human operator. In some embodiments, the payload can be completely autonomous so that its operation is preprogrammed with no remote human control or operational intervention after it is launched. In another embodiment, the payload can be semi-autonomous so that some or all of its operation is controlled remotely by one or more human operators after it is launched. 
         [0011]    In one embodiment, the payload can be a small folding version of a UAV with spring loaded, folding airfoils disposed in the fully sealed launch tube. Prior to launch, the launch tube can be pressurized with compressed gas that during launch is used to inflate the air bag ram which launches the payload from the launcher. The compressed gas can be any suitable compressible gas including, but not limited to, air, argon, nitrogen, helium, or the like. 
         [0012]    In one embodiment, the payload launch system comprises a pre-packaged payload loaded into the launch tube. A sealed cap can be fitted at an end of the launch tube sealing it from harsh environments and prevent ingress of water into the launch tube prior to launch. The launch system is pre-charged with compressed gas making it ready to launch locally or from a remote location. The payload launch system can be physically placed where needed for prolonged exposure. 
         [0013]    In one embodiment, the launch tube forms a reusable canister for launching payloads, such as UAVs, from a marine environment. The canister has an air bag ram attached at a base of the launch chamber to protect the dump valve. The dump valve is between a compressed gas storage chamber and the air bag ram at the base of the launch chamber. Without the protection of the air bag ram, the dump valve is susceptible to fouling from water and debris carried in from water. Prior to inflation and after inflation, the air bag ram seals with the interior surface of the launch tube. Further, when inflated, the air bag ram fills substantially the entire volume of the launch chamber. The air bag ram not only keeps debris from reaching the valve, it also keeps water from flooding the launch tube and sinking the launch tube in high sea states. In addition, the air bag ram creates added buoyancy to maintain the launch tube floating in the water after launch. 
         [0014]    The air bag ram seals the dump valve and other internal components of the canister from the water and debris. After inflation, the gas remains in the air bag ram until the gas is released through a relief valve. Because the air bag ram seals with the interior surface of the launch tube, the launch tube bore and surface finish of the launch tube bore are not critical, and a ram seal, for example on the air bag ram, can optionally be included but is not required. In addition, noise is contained and muffled in the air bag ram. Further, the air bag ram fills substantially the entire launch chamber when inflated and forms a sealed buoyancy volume that can be reduced or controlled with the relief valve after launch. 
     
    
     
       DRAWINGS 
         [0015]      FIG. 1  is a perspective view of the payload launch system. 
           [0016]      FIG. 2  is a cross-sectional side view of the payload launch system of  FIG. 1  prior to launch of the payload. 
           [0017]      FIG. 3  is a cross-sectional side view of the payload launch system of  FIG. 1  after launch of the payload. 
       
    
    
     DETAILED DESCRIPTION 
       [0018]    With reference initially to  FIG. 1 , one embodiment of a payload launch system  10  described herein is illustrated. The payload launch system  10  will be described herein as launching a payload while the payload launch system  10  is floating in water at the water surface. The water can be seawater, freshwater, or brackish water. However, the payload launch system  10  can be used on land to launch the payload from land, while the launch system is stationary or moving. 
         [0019]    For sake of convenience, the payload to be launched by the payload launch system  10  will be described as being a UAV that is designed to be launched into the air and once launched, fly under its own power performing a desired mission. However, the payload can be any unmanned payload that one may wish to transport and launch, and protect the payload from harsh environments for extended periods of time prior to launch. Other examples of payloads that can be launched include, but are not limited to, a balloon with a sensor package, munitions and many others. 
         [0020]    The launch system  10  in  FIG. 1  is shown in a stowed, ready to launch configuration. The launch system  10  includes a sealed launch tube  12  that is sealed at its bottom end by a service cap  14  and sealed at its top end by a releasable cap  16  that seals the top end of the tube  12  to prevent ingress of water and other contaminants into the launch tube  12  prior to launch. The tube  12  can be made from any material, for example steel, aluminum, or plastic, suitable for withstanding launch pressure and the environments within which the launch system  10  is used. 
         [0021]    The service cap  14  controls access to interior components within the base of the launch tube  12 . For example, the service cap  14  can include an electronics connection, for example an Ethernet port, permitting I/O connections to electronics within the launch system  10 . In addition, the service cap  14  can include a compressed gas filler port  18  through which a compressed gas storage chamber (discussed below) within the launch tube  12  can be charged with a compressed gas. 
         [0022]    The releasable cap  16  can be any form of cap that initially closes and seals the top end of the launch tube  12  to prevent ingress of water and other contaminants into the launch tube  12  prior to launch, and that can be removed, either automatically or manually, to permit launch of the payload from the launch tube  12 . Removal of the cap  16  is intended to include breaking of the cap  16  by the pressure of the launch of the payload from the launch tube  12 . Examples of releasable caps are described in U.S. Pat. Nos. 8,439,301, 8,205,829, 8,205,828, and U.S. Published Application Nos. 2011/0073707 and 2012/0043411. 
         [0023]    An inflatable float ring  20  is shown in  FIG. 1  as being connected to the launch tube  12  below the top end thereof. The float ring  20  causes the launch tube  12  to float at the surface of the water with the top end of the launch tube  12  above the surface of the water. It is to be realized that when launching from land or out of water applications, the float ring  20  is not utilized. 
         [0024]    The launch tube  12  can also include a communication antenna  22  through which communications can be sent to and from the launch system  10 . For example, launching of the payload can be triggered upon receipt of a launch signal; deflation of the float ring  20  can occur upon receipt of a suitable signal; the launch system  10  can transmit location data, sensory data, status data, and other data to a receiving location; and the like. 
         [0025]      FIG. 2  is a cross-sectional side view of the payload launch system  10  prior to launch of a payload. For sake of convenience, the cap  16  is not illustrated in  FIG. 2  although the cap  16  would normally be in place at the top end of the launch tube  12  prior to launch. The launch tube  12  defines a launch chamber  30  having an open first end  32  that is normally closed by the cap  16  prior to launch and a second end  34  opposite the open first end  32 . A payload  40  is disposed within the launch chamber  30 , with the payload  40  being launchable through the open first end  32  of the launch chamber  30  after removal of the cap  16 . The payload  40  can be a UAV or any other payload that one may want to launch from the launch tube  12 . 
         [0026]    A compressed gas storage chamber  42  is formed within the launch tube  12  at the base end thereof. The compressed gas storage chamber  42  is designed to be filled with and contain a compressed gas including, but not limited to, air, argon, nitrogen, helium, or the like, which is used to launch the payload  40  from the launch tune  12 . The gas storage chamber  42  can be charged with pressurized gas through the gas filler port  18 . 
         [0027]    A payload ejection mechanism is provided in the launch tube  12  for ejecting or launching the payload  40  through the first end  32 . The payload ejection mechanism is expandable from a pre-launch state where the payload ejection mechanism is located between the second end  34  and the payload  40  to an expanded state where the payload ejection mechanism occupies substantially the entire launch chamber  30 . In the illustrated embodiment, the payload ejection mechanism comprises an inflatable air bag ram  44  that is disposed at the second end  34  of the launch chamber  30 . The air bag ram  44  is disposed between a fixed wall  46  that defines the second end  34  or bottom end of the launch chamber  30  and the base of the payload  40 . The air bag ram  44  is in selective, controlled fluid communication with the gas storage chamber  42  via a dump valve  48 . The dump valve  48  is closed prior to launch, but can be automatically opened by a suitable control on the launch system  10  to permit rapid introduction of compressed gas from the gas storage chamber  42  into the air bag ram  44  to rapidly inflate the air bag ram  44  causing the air bag ram  44  to expand upwardly in the launch chamber  30  which ejects the payload  40  from the launch chamber  30 . Once the payload  40  is launched, the dump valve  48  can be closed to retain any residual compressed gas within the compressed gas storage chamber  42 . Operation of the dump valve  48  can occur automatically after a predetermined amount of time has elapsed, for example a predetermined amount of time after the launch system  10  is deployed into the water, by a signal received via the antenna  22 , based upon one or more sensed conditions around the launch system  10 , manually, or combinations thereof 
         [0028]      FIG. 2  illustrates the air bag ram  44  in its pre-launch compressed state within the launch chamber  30 .  FIG. 3  illustrates the air bag ram  44  in an expanded launch state within the launch chamber  30  after the dump valve  48  has been opened to eject the payload  40  from the launch chamber  30 . A ram plate  50  (illustrated in  FIGS. 2 and 3 ) can be fixed to the upper end of the air bag ram  44  and disposed between the air bag ram  44  and the payload  40 . In some embodiments, the ram plate  50  is not utilized, in which case an upper end of the air bag ram  44  can be in direct engagement with the base of the payload  40 . 
         [0029]    In both its pre-launch compressed state and its expanded launch state, the air bag ram  44  is sealed with an interior surface  52  of the launch tube  12  that defines the launch chamber  30 . The sealing provided by the air bag ram  44  prevents water and other contaminants from entering the launch tube  12  and reaching the dump valve  48 , thereby isolating the dump valve  48  from the water and other contaminants that could interfere with operation of the dump valve  48 , for example if the launch tube  12  is re-used. In an optional embodiment, the ram plate  50  (if used) can be in sealing engagement with the interior surface  52  either directly or via one or more separate seals, such as a lip seal, mounted on the ram plate  50 . In another optional embodiment, one or more separate seals can be provided on the air bag ram  44  to help seal with the interior surface  52 . 
         [0030]    Referring to  FIG. 3 , the air bag ram  44  fills substantially the entire launch chamber  30  when in its expanded launch state. In one embodiment, no portion of the air bag ram  44  extends out through the first end  32  of the launch tube  12  in the expanded launch state. In embodiments where the ram plate  50  is used, the ram plate  50  is pushed upwardly toward the first end  32 , but no portion of the ram plate  50  extends out through the first end  32  of the launch tube  12  in the expanded launch state as illustrated in  FIG. 3 . Because the air bag ram  44  fills substantially the entire launch chamber  30  when in its expanded launch state, and the air bag ram  44  seals with the interior surface  52  of the launch tube  12 , the air bag ram  44  prevents water from entering and filling the launch tube  12 . In addition, the expanded air bag ram  44  forms a sealed buoyancy volume that increases the buoyancy of the launch tube  12  to maintain the launch tube  12  floating in the water after launching the payload  40 . 
         [0031]    A relief valve  60  can be provided that is in fluid communication with the air bag ram  44  to reduce the amount of gas in the air bag ram  44  after launch. The relief valve  60  can be provided at any location on or in the launch tube  12  that permits access for reducing the amount of gas in the air bag ram  44 . In the example illustrated in  FIGS. 2 and 3 , the relief valve  60  is located so as to be accessible from an exterior of the launch tube  12 . For example, the relief valve  60  can be provided on an exterior of the launch tube  12  near a base of the air bag ram  44 . The relief valve  60  can be actuated open, manually or automatically, to allow gas to escape from the air bag ram  44 , thereby deflating the air bag ram  44  and reducing its buoyancy. In some embodiments, the relief valve  60  is not in fluid communication with the gas storage chamber  42  so only gas from the air bag ram  44  is drained through the relief valve  60 . However, if more complete removal of compressed gas from the system  10  is desired, the relief valve  60  could be in fluid communication with the gas storage chamber  42  and/or the dump valve  48  could be opened during draining of the air bag ram  44 . 
         [0032]    In embodiments where the launch system  12  is not intended to be re-used, the launch tube  12  can be made to sink after launching the payload  40 . For example, the float ring  20  can be provided with a scuttle patch that causes the float ring  20  to deflate, automatically or via actuation, after a period of time. In addition, the relief valve  60  can automatically open after a period of time to deflate the air bag ram  44  and/or the air bag ram  44  can be provided with a scuttle patch that causes the air bag ram  44  to deflate, automatically or via actuation, after a period of time. 
         [0033]    The payload launch system  10  can be transported to a desired launch location by a separate transport means where the launch system  10  is then deployed from the transport means. For example, the launch system  10  can be deployed underwater from a submarine, from an autonomous underwater vehicle, from a surface vessel, or manually by a swimmer or diver, with the launch system  10  subsequently floating to the water surface via the float ring  20 . The launch system  10  can also be deployed into the water from the air, for example dropped from a surface vessel or dropped from an aircraft. 
         [0034]    The examples disclosed in this application are to be considered in all respects as illustrative and not limitative. The scope of the invention is indicated by the appended claims rather than by the foregoing description; and all changes which come within the meaning and range of equivalency of the claims are intended to be embraced therein.