Abstract:
A small target weapon (STW) delivers a warhead to a remote target and detonates it in response to remote command signals from a swimmer delivery vehicle (SDV) and internal control signals generated by a self-contained internal electronics section. When deployed from the SDV, STW is capable of traveling several nautical miles underwater. The STW contains a warhead section and has a spool of optical fiber disposed aft to deploy optical fiber from the housing as it transits through water from a submerged delivery vehicle. Motor-driven propellers disposed aft on the housing of the STW propel it the through the water, and a mast member extends above the housing. Control fins disposed aft on the housing, a vertical thruster and the motor driven propellers are controlled by electronics sections and guidance and control sections to selectively keep the housing beneath the surface of the water and the mast member extending through the surface. Sensor systems on the mast member and a sonar system on the housing provide GPS data signals, optical data signals, non-visible radiation, and sonar data signals, and radio, acoustic, and optical command signals from the SDV steer the STW to and detonate warhead section at the target. GPS signals sensed on the mast member that extends above the water while the rest of STW is submerged assure navigation as STW traverses the distance from the SDV to the target. The cameras, non visible light sources, and antennas on mast member also may be used to locate, identify, and transit to the target. During the terminal phase of the run to the target, the STW may activate the onboard sonar to acquire and home-in on the target.

Description:
STATEMENT OF GOVERNMENT INTEREST 
     The invention described herein may be manufactured and used by or for the Government of the United States of America for governmental purposes without the payment of any royalties thereon or therefor. 
    
    
     BACKGROUND OF THE INVENTION 
     This invention relates to undersea vehicles guided to a remote location. More particularly, this invention provides an undersea small target weapon remotely controlled and guided by remote signals and/or onboard navigational systems to a distant target where it is detonated. 
     Currently, no multi navigational capability exists for submerged deployment of ordnance to a target located at a safe standoff distance several nautical miles from a submerged command station. When their single mode of guidance is frustrated or a component fails in most torpedo-like vehicles, a mission goes down, and, usually, greater risks must be taken to successfully complete it. In particular, underwater navigation or imaging an area underwater at night with non-visible light and/or onboard sonar hasn&#39;t been combined within the body of a small weapon that is remotely operated. No undersea compact weapon has a camera with attached GPS antenna, non-visible light source, and sonar. 
     Thus, in accordance with this inventive concept, a need has been recognized in the state of the art for a small target weapon for a warhead guided to a distant target from a control station by combined navigational aids including visual and/or infrared cameras, GPS with an attached GPS antenna, non-visible light sources, and sonars. 
     SUMMARY OF THE INVENTION 
     The present invention provides an unmanned submersible including an elongate housing containing a warhead section and having a spool of optical fiber disposed aft to deploy optical fiber from the housing as it transits through water from a submerged delivery vehicle. Motor-driven propellers disposed aft on the housing radially outwardly from the spool of optical fiber provide propulsion through the water, and a mast member disposed forward on the housing extends above the housing and the surface of the water. Fins disposed aft on the housing, a vertical thruster having a propeller assembly, and the motor driven propellers are controlled by electronics and guidance and control sections to selectively maintain the housing beneath the surface of the water and keep the mast member extending through the surface. Sensor systems on the mast member and a sonar system on the housing provide GPS data signals, optical data signals, non-visible radiation and sonar data signals, and radio, acoustic, and optical command signals from the submerged delivery vehicle steer it to and detonate warhead section at the target. 
     An object of the invention is to provide a small target weapon capable of neutralizing a target of interest at a safe standoff distance of several nautical miles from a swimmer delivery vehicle. 
     Another object of the invention is to provide a remotely guided, small target weapon capable of underwater navigation and/or imaging underwater at night with onboard sonar and/or non-visible light source. 
     Another object of the invention is to provide an undersea small target weapon incorporating a camera with an attached GPS antenna, non-visible light source, and sonar. 
     Another object is to provide an underwater small target weapon providing remote visual inspection of a target prior to neutralization. 
     Another object is to provide a small target weapon having sonar to detect obstacles or underwater threats. 
     An object of the invention is to provide an undersea small target weapon having a camera system operating in spectrums not easily detected by the human eye. 
     Another object is to provide a submersible small target weapon having a camera system and GPS antenna on the same mast member. 
     These and other objects of the invention will become more readily apparent from the ensuing specification when taken in conjunction with the appended claims. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a schematic cross-sectional top view of the small target weapon of this invention. 
     FIG. 2 is a schematic cross-sectional side view of the small target weapon of this invention. 
     FIG. 3 is an end view of the small target weapon. 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT 
     Referring to FIGS. 1,  2 , and  3 , small target weapon (STW)  10  of this invention is an unmanned submersible controlled during its submerged transit from a distant swimmer delivery vehicle (SDV)  60  to target  70 . STW  10  and SDV  60  usually complete their mission entirely underwater, and STW  10  is sized to be transported by and deployed from SDV  60 , although STW  10  could be transported by air to the region of target  70  and SDV  60  and airdropped via a releasable parachute when this type of deployment would be expedient. 
     Command signals  61  are transmitted from SDV  60  as acoustic command signals  61   a  in water  50 , optical command signals  61   b  in optical fiber  62  that unspools from spool  63  as STW  10  continues toward target  70 , or radio command signals  61   c  from SDV  60  or signals  65   a  from some other remote command station  60   a.  Command signals  61  control STW  10  and bring it in contact with, or at least come within a lethal radius of target  70 . 
     STW  10  has elongate box-shaped or cylindrically-shaped housing  12 . Either shaped housing  12  can be made from metal or lightweight synthetic materials having sufficient strength to bear pressures exerted by ambient water as STW  10  dives to avoid detection, maneuvers, and proceeds submerged during completion of a mission. 
     Four elongate pylons  13   a,    13   b,    13   c,  and  13   d  are orthogonally, symmetrically mounted about housing  12  and longitudinally extend the length of housing  12 . Pylons  13   a,    13   b,    13   c,  and  13   d  each contain batteries  13 ′ and possibly some electronics for control purposes. Batteries  13 ′ may be appropriately coupled to power sections and modules to be described. Each pylon houses an electric motor  14  for rotating a propeller  15  aft on housing  12 . Each electric motor  14  is connected to battery section  11  inside housing  12  for power to propel STW  10 . 
     Mast member  16  extends from pylon  13   a  forward on housing  12  and supports camera system  18  above housing  12 . As STW  10  transits to the region of target  70  just below surface  51  of water  50 , the smaller, less conspicuous camera system  18  may be periodically, or continuously above surface  51  and the larger bulk of STW  10  is not readily detectable visually or by radar. Camera system  18  has a combination of optical sensing and imaging devices for light that includes radiations in the visible, infrared, and ultraviolet spectrums, and for other radiations in other spectrums. The appropriate sensors, imagers, receivers, detectors, etc., may be contained in mast member  16 , or they may be located inside housing  12  and suitably connected to appropriate lenses, optical fibers, waveguides, antennas, and appropriate conductors of such radiations in mast member  16 . In either case, the data signals provided by camera system  18  are fed to processing, logic, and relay modules (not shown) in electronics section  38  in housing  12 . 
     GPS antenna  20  is mounted adjacent to camera system  18  at the upper surface of mast member  16 . GPS antenna  20  is held above surface  51  as mast member  16  extends through it. This small exposure of GPS antenna  20  is enough to sense GPS data signals representative of the position of STW  10  from orbiting satellites without compromising the location of STW  10 . The received GPS data signals can be used for steering STW  10  and may be relayed to SDV  60  for tactical purposes. 
     Radio antenna  22  is mounted on mast member  16  to be above surface  51  and receive radio command signals  61   c  transmitted from surfaced SDV  60 , or other distant command stations (not shown). Radio antenna  22  also can transmit radio data signals  64   d  to distant stations if desired. 
     Non-visible light source system  24  is mounted on mast member  16  to place it above the surface  51  during near-surface transit of STW  10 . Non-visible light source system  24  can emit radiation in the infrared, ultraviolet, or other spectrums that are non-visible to irradiate, or illuminate objects above surface  51  and below in water  50  including target  70 . Appropriate sensors in camera system  18  receive reflected portions of the non-visible radiation and provide representative data signals of ambient features for appropriate processing in STW  10  to avoid obstacles, for example, and relay the received data to SDV  60 . 
     The small size and usually intermittent limited exposure of non-visible light system  24 , radio antenna  22 , GPS antenna  20 , camera system  18 , and mast member  16  do not draw attention to them. These sensors do not need to be exposed above surface  51  for the duration or final phases of a mission, but are exposed only when it is safe to check progress along a course. Thus, the submerged bulk of STW  10  is hidden in water  50  as position information, command signals, and other data is received and relayed while STW  10  proceeds to target  70 . 
     Sonar system  26  is located low and forward on housing  12  on pylon  13   d  and has at least one transducer to project acoustic energy through water  50  to ensonify a region. The same transducer, or at least one other transducer of sonar system  26  receives reflected portions of the ensonifying acoustic energy (like a hydrophone) to provide acoustic data signals representative of ambient marine features, such as target  70  and marine topography. Sonar system  26  may be restricted in range to about one hundred meters for acoustic homing during the terminal phase to target  70 . However, in addition to terminal phase homing, transducers and internal processor modules in electronics section  38  of sonar system  26  can have increased capabilities to allow acoustic communications by transmitting acoustic data signals  64   a  and receiving acoustic command signals  61   a  to and from SDV  60  and other stations. 
     The information of the received data signals from camera system  18 , GPS antenna  20 , radio antenna  22 , non-visible light source  24 , and sonar system  26 , can be utilized separately or in combination by onboard processing modules in electronics section  38  for navigation, avoidance of obstacles, and countermeasures by STW  10 . Selected portions of the information can be relayed to SDV  60  via acoustic data signals  64   a  from sonar system  26 , optical data signals  64   b  over optical fiber  62 , and radio data signals  64   d.  GPS data signals  64   c  can be relayed back as part of the signals of acoustic data signals  64   a,  optical data signals  64   c,  and/or radio data signals  64   d.    
     An impact switch, or contact detonator  28  is carried on the forward most part of housing  12 . When STW  10  is driven into target  70 , impact switch  28  initiates detonation of warhead section  30 . Warhead section  30  can be a bulk or shaped charge of many different explosives with appropriate fusing, detonators, and boosters to detonate reliably and disable or destroy target  70 . Warhead section  30  can include a detonator (not shown) to detonate warhead section  30  when STW  10  is in the proximity, or lethal radius of target  70 . This proximity detonator can be activated when acoustic targeting signals are projected from a transducer of sonar system  26  and are received as reflected acoustic target signals by a hydrophone transducer of sonar system  26 . The proximity detector can be preset to detonate warhead section  30  when the received reflected acoustic target signals indicate that STW  10  is within the lethal radius of target  70 . Warhead section  30  could include another detonator (not shown) that is initiated to detonate it when an appropriate command signal  61   a,    61   b,  or  61   c  is received by STW  10 . This gives an operator in SDV  60  the option to detonate warhead section  30  at target  70  or at some other target of opportunity during a mission. 
     STW  10  is guided to impact target  60  by controlling pivotable horizontal control fins  32   a  and  32   b,  pivotable vertical control fins  33   a  and  33   b,  and vertical tunnel thruster  34  next to warhead section  30 . The four control fins  32   a,    32   b,    33   a,  and  33   b  are symmetrically, orthogonally mounted aft about housing  12 . Fins  32   a  and  32   b  are selectably rotated by interconnected electric motors (not shown) separately or together about a horizontal axis through STW  10 , and fins  33   a  and  33   b  are selectably rotated by interconnected electric motors (not shown) separately or together about a vertical axis through STW  10 . Thus, each of control fins  32   a,    32   b,    33   a,  and  33   b  may be selectably rotated so that STW  10  can turn, bank, pitch, roll, dive, and climb as it progresses to target  70 . These control fins could also have a variety of flaps and vented surfaces to function as additional control surfaces if desired. Although FIG. 2 shows fin  33   a  extending through surface  51 , fin  33   a  may be made smaller to keep it below surface  51 , or STW  10  may come to surface  51  at an incline to keep fin  33   a  submerged. 
     Vertical tunnel thruster  34  can be a shrouded electric motor-driven single propeller or counter rotating propeller assembly  34   a  to hover STW  10  while it is stopped and not proceeding forward. In addition, tunnel thruster  34  can augment the controlled upward and downward motions of STW  10  created by rotation of horizontal fins  32   a  and  32   b  when STW  10  is in transit. Appropriate rotation of propeller assembly  34   a  of thruster  34  can sustain, or hover STW  10  at a desired depth beneath surface  51 , or such rotation of assembly  34  can hold mast member  16  and its systems and antennas above the surface of water  50  while STW  10  is in transit or at rest to assure reliable operation for the duration. This feature permits STW  10  to cruise with mast member  16  out of the water and hover while remaining motionless beneath surface  51 . While hovering, mast member  16  extending through surface  51  does not create a visible wake on water  50 . 
     In addition to the selective control of STW  10  that is implemented by fins  32   a,    32   b,    33   a,  and  33   d  and tunnel thruster  34 , electric motors  14  can be reversed to selectably reverse the rotation of propellers  15 . Propellers  15  are symmetrically, orthogonally mounted aft about housing  12  in-line with pylons  13   a,    13   b,    13   c,  and  13   d  to effect responsive control of STW  10 . Propellers  15  are located radially outwardly from optical fiber spool  63  to avoid breaking optical fiber  62  as it unspools during transit of STW  10 . Reversible, controllable propellers  15  can further augment maneuvering of STW  10  to avoid obstacles and proceed to target  70 ; however, care must be exercised not to sever optical fiber  62 . Actuating signals for the motors connected to fins  32   a,    32   b,    33   a,    33   b,  tunnel thruster section  34  and propellers  15  are created in guidance and control section  36 . 
     Guidance and control section  36  generates actuating signals at the proper magnitudes and durations in response to internal control signals created in electronics section  38 . In accordance with many such systems known in the art, actuating signals from modules in guidance and control section  36  are suitably coupled to effect responsive displacements of electric motors connected to fins  32   a,    32   b,    33   a,  and  33   b,  tunnel thruster  34 , and propellers  15  to responsively steer and guide STW  10  in direction, speed, depth, and evasive maneuvers to target  70 . The power for operation of guidance and control section  36  and for the motors connected to the fins, thruster, and propellers comes through suitable connections extending to both battery section  11  and batteries  13 ′. 
     Electronics section  36  in housing  12  has processing and logic modules (not shown) coupled to receive the data signals from camera system  18 , GPS antenna  20 , radio antenna  22 , and sonar system  26 . The processing and logic modules included electronics section  36  are well known in the art and are included in STW  10  to process incoming data signals from camera system  18 , GPS antenna  20 , radio antenna  22 , and sonar system  26 , to create appropriate internal control signals, and feed these internal control signals to guidance and control section  36 . Electronics section  36  additionally has processing, logic and transceiver modules responsive to acoustic command signals  61   a  received by hydrophone transducer of sonar system  26 , optical command signals  61   b  received over optical fiber  62 , and radio command signals  61   c  received by radio antenna  22 . When these command signals are coupled to electronics section  36 , appropriate processing and logic modules in electronics section  36  create internal control signals for guidance and control section  36  for generation of actuating signals. These actuating signals responsively steer and guide STW  10  in direction, speed, depth, and evasive maneuvers to target  70 . Thus, the combination of controllable fins and propellers gives STW  10  great maneuverability to surmount obstacles, evade countermeasures, and precisely deliver weapon section  30  to target  70 . 
     STW  10  in accordance with this invention is an underwater weapon carried to the region of target  70  by SDV  60  to deliver warhead section  30  to neutralize target  70  and other targets of opportunity. After being deployed from SDV  60 , STW  10  has sufficient power in battery section  11  and batteries  13 ′ to travel several nautical miles underwater. Electronics section  38  in housing  12  has processing and logic modules (not shown) coupled to receive the data signals from camera system  18 , GPS antenna  20 , radio antenna  22 , and sonar system  26 . The processing and logic modules included in electronics section  38  are well known in the art and are included in STW  10  to process incoming data signals from camera system  18 , GPS antenna  20 , radio antenna  22 , and sonar system  26 , to create appropriate internal control signals, and feed these internal control signals to guidance and control section  36 . Electronics section  38  additionally has processing, logic and transceiver modules responsive to acoustic command signals  61   a  received by hydrophone transducer of sonar system  26 , optical command signals  61   b  received over optical fiber  62 , and radio command signals  61   c  received by radio antenna  22 . When these command signals are coupled to electronics section  38 , appropriate processing and logic modules in electronics section  38  create internal control signals for guidance and control section  36  for generation of actuating signals. These actuating signals responsively steer and guide STW  10  in direction, speed, depth, and evasive maneuvers to target  70 . Thus, the combination of controllable fins and propellers gives STW  10  great maneuverability to surmount obstacles, evade countermeasures, and precisely deliver weapon section  30  to target  70 . 
     Operational deployment of STW  10  begins with coming within range of target  70 , separating STW  10  a safe distance from SDV  60 , and powering-up STW  10 . During this procedure, both STW  10  and SDV  60  are underwater and cannot be seen. An operator in SDV  60  performs a series of tests to check the functions of STW  10 . Appropriate modules in sections  11 ,  30 ,  36 , and  38  in STW  10  are preprogrammed and activated to enable STW  10  to run a predetermined, preprogrammed course to target  70 . At a safe standoff distance which is beyond the distance that the explosion of warhead section  30  can be tolerated  30 , a safe and arm mechanism associated with warhead section  30  begins to arm section  30 . When complete, the operator sends command signals  61   a,    61   b,  or  61   c  to initiate motor-driven propellers  15 . Another command signal  61   a,    61   b,  or  61   c  from the operator may cause STW  10  to proceed beneath surface  51   50  at a depth just below surface  51 . This depth keeps camera system  18  above the surface so that appropriate consoles being monitored by the operator can be used to guide STW  10  to target  70 . While STW  10  is traversing to target  70 , the position of STW  10 , as indicated by GPS signals received by GPS antenna  20 , is relayed to and displayed on the operator&#39;s control console. 
     Should the operator desire to approach target  70  undetected, appropriate command signals can be sent to STW  10  to cause it to dive to and proceed at a depth where camera system  18  is no longer held above the surface but GPS antenna  20  is still above the surface. GPS data signals  64   c  can be transmitted from STW  10  to SDV  60  as acoustic data signals  64   a,  optical data signals  64   b,  and/or radio data signals  64   d  if radio antenna  22  extends through surface  51 . The operator can then navigate STW  10  using the navigational information of GPS signals received by GPS antenna  20  and known target location. After STW  10  is within the terminal homing capability of sonar system  26 , STW  10  may be programmed in electronics section  38  to automatically begin a terminal run to target  70 . STW  10  may detonate on contact with target  70  or it can be detonated by command signals  61  from the operator. 
     STW  10  can operate in the automatic or manual mode. Either way, STW  10  is capable of performing remote neutralization of targets while at a safe standoff distance for the crew of SDV  60 . The automatic mode uses GPS signals during preprogrammed initial phases and has sonar system  26  in the terminal phase to provide tactical information to guide STW  10  to target  70 . In automatic mode contact of impact switch  28  with target  70  initiates detonation of warhead section  30 , although proximity detection might be relied upon for detonation. 
     In the manual mode the operator in SDV  60  controls STW  10  to the target and then initiates detonation of the weapon from an on board control console (not shown) in SDV  60 . Once STW  10  is deployed from SDV  60 , the control console allows control of STW  10  for the duration of the selected mission and has four displays, the tactical display, touch screen, sonar display, and video display. The tactical display provides a scenario including, position, attitude, and status of STW  10 , target  70  or desired GPS location of target  70 , sonar search sector of STW  10 , and environmental data. The touch screen allows control of STW  10  during all phases of the mission. The sonar display can be active search format, or can provide a passive capability for some targets. The sector azimuth of sonar system  26  can be selected during run out of STW  10  and may be progressively narrowed as STW  10  approaches the region of target  70 . Signals representative of the video display are sent from STW  10  via optical data signals  64   b  over optical fiber  62 . 
     In either mode acoustic signals of sonar system  26  can provide for underwater navigation when the operator decides to navigate using known underwater landmarks. Non-visible light source  24  on mast member  16  permits the operator on SDV  60  to use camera system  18  underwater, above water, and/or at night while avoiding detection from the surface. The combination of non-visible light source  24  and optical sensing and imaging devices for non-visible spectrums of camera system  18  is another navigation tool for the operator that allows inspection of target  70  in the manual mode of operation, or interdiction activities. 
     In accordance with this invention STW  10  is deployed from SDV  60  and the operator in SDV  60  takes control of STW  10  and begins transiting to the intended GPS location of target  70  in either the manual or automatic mode. While traversing to target  70  during the initial phase, the operator can bring STW  10  to within a half meter of surface  51 . GPS antenna  20  on mast member  16  receives GPS signals from orbiting satellites and feeds them to modules of a GPS processing system in electronics section  38  to guide STW  10  to the proper location. Since camera system  18  is above surface  51 , the location of STW  10  as established by the GPS signals can be verified. The accurate tracking provided by visual and/or other spectral monitoring via camera system  18  and/or GPS tracking can be done intermittently or continuously on the way to target  70 . Once STW  10  is in the desired region of target  70 , the operator surveys it in detail via camera system  18 . Vertical tunnel thruster  34  provides station keeping, or hovering to permit detailed inspection of target  70  for a number of purposes. The capabilities of camera system  18  may be used to precisely position STW  10  manually and the operator gives the command to detonate warhead section  30 . 
     In the automatic mode, GPS coordinates indicative of the location of target  70  would be programmed into the appropriate modules of the GPS system in electronics section  38 . In response to internal control signals from electronics section  38 , appropriate actuating signals from guidance and control unit  36  would steer STW  10  along a predetermined course to bring target  70  within the range of sonar system  26 . Target  70  is acquired by the transducers and the modules associated with sonar system  26 , and electronics section  38  and guidance and control section  36  respond to ranging data of sonar system  26  to steer STW  10  during a terminal stage into target  70  for detonation of warhead section  30 . 
     Having the teachings of this invention in mind, modifications and alternate embodiments of this invention may be adapted. STW  10  can be made in many different sizes and configurations for reliable operation in different operational scenarios. Thus, STW  10  additionally can be used for round-trip missions such as, the unobserved delivery of packages, ordnance, electronics, supplies, etc. 
     The disclosed components and their arrangements as disclosed herein all contribute to the novel features of this invention. STW  10  provides a covert, quick and cost-effective way to deliver ordnance to an undersea target without introducing unnecessary complications or exposing personnel to danger. Therefore, STW  10 , as disclosed herein is not to be construed as limiting, but rather, is intended to be demonstrative of this inventive concept. 
     It should be readily understood that many modifications and variations of the present invention are possible within the purview of the claimed invention. It is to be understood that within the scope of the appended claims the invention may be practiced otherwise than as specifically described.