Abstract: A system is provided to coalesce bubbles in the wake of a structure that rces the surface of the water. Acoustic sources mounted to the structure produce a plurality of plane waves above and below the surface of the water. The plane waves intersect to create a plurality of standing wave fields both above and below the surface of the water. The standing wave fields operate on bubbles in the wake to coalesce same.

Abstract: A receiver and method are disclosed that improves signal detection in a mipath environment wherein the desired reflected acoustic pulse is degraded by multipath reflections and embedded in noise. The invention provides a receiver that repetitively processes the received signal. The receiver includes separate signal processors, such as parallel configured quadrature signal processors, wherein each processor operates over different, and preferably contiguous, time intervals. After each repetition, the processing time interval for each processor is changed. The outputs of the processors are combined, such as by summing, and applied to a detector, such as a threshold detector, for each processing repetition to determine if the transmitted pulse is detected. The receiver continues processing the received signal until a predetermined number of time intervals have been processed without detection of a pulse or until the reflected pulse is detected.

Abstract: An interlink for connecting hydrophone elements to allow a single sensing ber to transition from a first hydrophone element, across the interlink, to a second hydrophone element. The interlink satisfies the dual objective of protecting the sensing fiber during handling system stresses, while desensitizing the sensing fiber along the interlink during operational periods. The interlink has a first end connected to the first hydrophone element, and a second end connected to the second hydrophone element. Between the interlink ends is at least one turn, and the distance traveled along the interlink turns is greater than the linear distance between the interlink ends. The interlink contains a groove that traverses the entire interlink length. Sensing fiber is wound off the first hydrophone element, into the interlink groove that follows the interlink turns, and onto the second hydrophone element.

Abstract: A horizontal plasma antenna is provided. An ionizer generates an ionizing am through a horizontal tube to form a bounded plasma column extending along a horizontal axis in a gravity field. An amplitude or frequency modulating signal is applied to Helmholtz coils to control a horizontal magnetic field that is perpendicular to the horizontal axis. The resulting changes in the magnetic field produce a drift current in the plasma that, in turn, radiates an amplitude or phase modulated electromagnetic field from the plasma column.

Abstract: A broadband phased antenna is comprised of multiple patches which are dirly feed. The multiple patches provide the broadband patch antenna having overlapping narrow frequency bands and comprise a ground-plane element, multiple antenna elements, multiple dielectric layers, an RF feed line, and a feed arrangement. The ground-plane element has predetermined length and width dimensions and an aperture therein at a predetermined location near its center. The multiple antenna elements have an uppermost antenna element. The multiple dielectric layers are respectively interposed between and separate the multiple antenna elements into a stacked arrangement having odd and even numbered antenna elements.

Abstract: This invention relates to a secure marine communication system and especiy to a sonic communication system utilizing the so-called "sound channel" in the ocean deeps.The propagation of sound in sea water is known to occur along rays which are subject to refraction by variations in sound velocity. In most areas of the oceans, the velocity of sound varies with depth and temperature, and is less at some intermediate depth than it is either at the surface or at the ocean bottom. These oceanographic conditions produce a "sound channel" having at/its horizontal axis a level along which the velocity of sound reaches its minimum value. Essentially, the sound channel provides for a long-range transmission of sound between a sound source and a receiver where both types of sonic equipment are located at a level approximately corresponding to the axis of minimum velocity.

Abstract: An actuated recoil absorbing mounting system is used to reduce recoil velties and to absorb the recoil energy from an underwater projectile launcher, such as a high discharge energy underwater gun. The recoil absorbing mounting system includes a projectile launcher frame that supports the projectile launcher during firing. The projectile launcher frame is slideably supported by one or more launcher frame supports to allow movement substantially in a linear direction. One or more recoil plates are coupled to the underwater projectile launcher frame to provide hydrodynamic added or virtual mass and damping to the projectile launcher frame and projectile launcher. The recoil absorbing mounting system further includes one or more actuators for repositioning or returning the projectile launcher frame and projectile launcher to an original position after firing.

Abstract: The invention provides an unmanned, autonomous, undersea platform which ends the sphere of influence of a host vessel from which it is launched. The platform is hydrodynamically and stealth shaped to minimize noise, wake and detectability of the platform. The platform includes advanced active and passive sensors for monitoring the undersea environment, high data rate RF and satellite communications capabilities for communication with the host vessel when necessary, forward deployed offensive and defensive weapons systems and sophisticated data processing to coordinate the sensing, communications and weapons systems with minimal direction from the host vessel. Prior to launch, mission directives are input to the data processors. Using artificial intelligence and neural network programming for decision making, the processors constantly update the platform's operating parameters to conform with changing environmental and threat conditions and to successfully complete the mission.

Abstract: The present invention relates to a method and a system for providing an estimate of the state of a contact. The method includes the steps of sensing the state of the contact; generating signals representative of the state of the contact; and processing the signals using a random search procedure to arrive at an estimate of the state of the contact. The random search procedure may employ the simulated annealing-based algorithm methodology or the genetic-based algorithm methodologies. The system includes sensors for sensing the state of the contact and a pre-programmed computer for generating the desired contact state estimates.

Abstract: A real-time data acquisition system for a remote, unmanned underwater vehe includes an array of sensors within the vehicle which gather data from the environment surrounding the vehicle. The sensor data is digitized and stored in an imbedded computer on the unmanned vehicle. To display the data, the imbedded computer transfers the digital data over a local area network connection to a second computer aboard a mother ship. The second computer converts the digital data back to analog data for display. The data can also be analyzed and processed depending on test requirements. To test the unmanned vehicle performance, the vehicle can be operated adjacent the mother ship with the local area network connection in place. In this mode, the imbedded computer transfers the digital data to the second computer as the data is being stored in the imbedded computer.

Abstract: The invention is directed to a grommet including a cylindrical body fabried from rubber or synthetic rubber material. The body has a centrally located aperture extending therethrough and at least one radially located aperture with a slit for easily receiving a cable or the like. The grommet further includes a rigid insert secured to the body in the centrally located aperture. The insert has female threads formed therein for releasably securing a tool thereto to remove the grommet from the ballast tank without destroying the body of the grommet. The insert has a tubular member and an outwardly projecting circumferential flange formed on the tubular member. The body is formed on the tubular member wherein the flange secures the insert axially with respect to the body. Preferably, the body is fabricated from neoprene and is vulcanized to its final form.

Abstract: A mine placement system is provided for determining mine launch parameters ased on launcher vehicle position, speed, and direction and on latitude. The system includes an input module for receiving launcher vehicle position, speed, and direction having a settable aim point. The input module is connected to a processor module which continuously calculates the trajectory of the mine as the launch ship maneuvers. The processor module having a vectorizer, a decoder, a time processing unit and gyroprocessing unit drives a launch display having steering cursors and a range display. The steering cursors and range display provide maneuver information to the ship's operator to steer the ship to a launch window which will allow a mine to deploy to the set aim point. In addition to displaying the set aim point, the display also shows the present actual mine placement point based on the launch ships present location and velocity. Whenever a mine is launched, the system records the actual mine placement point.

Abstract: A process is provided for producing layouts of building units on a quadrieral facility site, and layouts of personnel workstations and items of equipment (collectively "workplace elements") in quadrilateral subarea in the building units. There are inter-building-unit, and inter-workplace-element, operational criteria associated with the activity being performed in the facility. The well known multi-dimensional scaling (MDS) methodology is employed in optimizing building unit and workplace element configurations to suit the operational criteria. Measurement of population density index (PDI) is employed to judge whether candidate configurations of building units and workplace elements result in adverse crowdedness conditions. The PDI employed for this purpose is novel. The novelty of the PDI is its use of a "convex hull" (in the mathematical sense of the term) circumscribed about the perimetrical objects in a candidate configuration.

Abstract: An interlink for connecting hydrophone elements that allows a single sens fiber to transition from a first hydrophone element, across the interlink, to a second hydrophone element, while providing a secure connection between hydrophone elements without the disadvantages of mechanical resonances produced by a rigid interlink material. The interlink has a first end connected to a first hydrophone element, and a second end connected to a second hydrophone element. The interlink may be composed entirely of open cell foam, or a more rigid structure that is covered by open cell foam. Sensing fiber transitions from a first hydrophone element, onto the foam interlink, and thence onto a second hydrophone element, with only a change in winding angle. The sensing fiber is not susceptible to a rigid interlink structure and undesirable mechanical resonances.

Abstract: A deflection snubber assembly for preventing damage to a propeller which is subjected to instances of high force is disclosed. The propeller includes a hub for mounting the propeller on a shaft and a number of blades exteng radially outward from the hub. Outer tips of the number of blades are interconnected by a continuous, circular band. The propeller is constructed to accommodate a predetermined amount of deflection upon instances of high force before being permanently damaged. The deflection snubber assembly includes a housing circumferentially surrounding the propeller, the housing having a number of deflection limiting members, each of the deflection limiting members limiting deflection of the propeller to within the predetermined amount of deflection upon occurrences of the instances of high force.

Abstract: An isolated compensated fluid delivery system is used in an underwater vel, such as a torpedo, to deliver a supply fluid such as fuel, while displacing the supply fluid with a compensating fluid to compensate for change in buoyancy of the underwater vessel. The buoyancy compensated fluid delivery system includes a container, such as a fuel tank, a flexible delivery chamber disposed within the container adjacent a flexible compensation chamber. An outlet is coupled to the flexible delivery chamber and extends outside the container to direct the supply fluid out of the flexible delivery chamber. An inlet is coupled to the flexible compensation chamber and extends outside the container to direct the compensating fluid into the flexible compensation chamber as the supply fluid is being delivered. The volume of compensating fluid is substantially equivalent to the volume of supply fluid such that the weight and displacement of the underwater vessel remains substantially constant.

Abstract: A hydrophone interlink that connects hydrophone elements and allows a sin sensing fiber to transition between hydrophone elements. The interlink has an outer-structure and a contained element. The outer-structure connects the hydrophone elements and has at least one turn such that the distance traveled along the turns exceeds the linear distance between hydrophone elements. The outer-structure material and shape allow temporary interlink stretching and compression during passes through handling sheaves, with memory to allow the interlink to return to its original shape. The outer-structure contains a groove on either end to transition the sensing fiber between the hydrophone elements and the contained element. The contained element is open cell foam that fills the hollow core of the outer-structure.

Abstract: An acoustic test assembly for testing an underwater vehicle includes a high pressure source joined by a high pressure pipe which extends into a fluid filled testing structure. A vibration shielding flange is joined to the sting structure wall where the flange supports the high pressure pipe. At least one acoustic barrier is positioned around the pipe inside the testing structure to isolate vibrations from the high pressure pipe. In further detail, the high pressure pipe is a pipe surrounded by thermal insulation and a sleeve preventing fluid from affecting the insulation. The acoustic barrier has a barrier joined by spacer means to the sleeve member.

Abstract: A fluid conduit for flowing electrically conductive fluids includes an elrically conductive pipe, an electrically conductive rod extending axially through the pipe and centrally thereof, a first power source in electrical communication with the pipe and rod, a solenoidal electromagnet disposed around the pipe and a second power source in electrical communication with the electromagnet. Activation of the first and second power sources creates an electric and a magnetic field, respectively, within the pipe which interact and result in a circumferential force in the flow with consequent reduction in wall friction in the pipe.

Abstract: A process is provided for coating a given surface of a heat sensitive metal article (e.g., thermally massive aluminum) with a high-cure-temperatureating-forming-powder. A first oven heating step elevates the metal article's temperature to a predetermined preheat cycle high-limit-of-heat-load-temperature. After a first predetermined period of time, the metal alloy article is withdrawn from the oven. A high-cure-temperature-coating-forming-powder is then sprayed onto the given surface of the metal article. The spraying, comprising first and second spray sequences, is initiated essentially immediately after withdrawal of the metal article from the oven. The first spray sequence is a single group of spray passes that applies a coating layer to fill the pores in the given surface with heat melted high-cure-temperature-coating-forming-powder. The second spray sequence builds up the total thickness of coating.