Abstract: A differential hydrophone assembly includes a ceramic hydrophone for disption in a water environment and comprising first and second hemispherical piezoelectric sections, a polarized ceramic member disposed in each section, a positive electrode and a negative electrode disposed in each section, an output conductor extending from each of the electrodes, such that a first pair of the conductors extend from a first of the ceramic members, and a second pair of the conductors extend from a second of the ceramic members, the first pair of conductors being discrete from the second pair of conductors. The assembly further includes a differential summing amplifier for disposition in a second environment removed from the water environment and electrically connected to the first and second pairs of conductors.

Abstract: An efficient and cost effective analog telemetry system for transmitting receiving many individual data channels over long distances is provided by having each data channel signal modulate a pseudo-random number (PRN) signal which has been delayed for a distinct number of clock cycles for each data channel. The modulated PRN signals are then outputted to a single data line and summed. At the remote receiver, each data signal is recovered by cross correlating the modulated PRN signals with individual reference PRN signals. A synchronous delay generator in each data channel properly aligns each reference signal in time with its corresponding modulated PRN signal. Other modulated PRN signals, which are not aligned with the proper reference PRN signal, are rejected.

Abstract: An improved method of having an SCSI controller provide a logical connect between a plurality of host processors using a single SCSI initiator. The controller contains removable host adapters for connection to any type of host processor interface. When a host processor requests status information of a target device, that status information is passed to the requesting processor and subsequently stored in the controller and made available to all other host processors. The advantage to such a controller is the expanded number of host processor connections to a single SCSI initiator whereby each host processor can independently and logically connect through the controller and SCSI initiator to a target without clearing target status information for other host processors. The invention is particularly advantageous when adapted to function in a local area network (LAN) arrangement where a significant number of host processors are requesting data from one mass storage device.

Abstract: A retractable seal replaces the existing o-ring seals on the Tomahawk Cape Launching System (CLS). An elastomeric member is shaped to fit within the existing o-ring slot on the CLS and a cylindrical ring member of shape memory alloy circumscribes the elastomeric member. Under normal operating temperatures, the shape memory alloy member has a diameter large enough to allow the elastomeric member to extend beyond the diameter of the CLS so as to form a seal against the missile tube, yet small enough to not interfere with the seal. When the shape memory alloy member is heated, it contracts to a smaller predetermined diameter, compressing the elastomeric member within the o-ring slot so as to allow the movement of the CLS into or out of the missile tube without abrading the elastomeric member.

Abstract: A method for recording operational data relating to submarine operations is provided including means for playing back the recorded data thereby proing a near real time playback and analysis for the submarine's crew and/or shore based facilities.

Abstract: An improved SCSI controller provides a logical connection between a pluray of host processors using a single SCSI initiator. The controller contains removable host adapters for connection to any type of host processor interface. When a host processor requests status information of a target device, that status information is passed to the requesting processor and subsequently stored in the controller and made available to all other host processors. In addition, a fault tolerant performance monitoring algorithm, executing within the controller, is scheduled to non-intrusively and periodically check the status of each SCSI target device and to store that status information for all host processors. The advantage to such a controller is that by using a single SCSI initiator, each host processor can independently and logically connect through the controller and SCSI initiator to a target without clearing target status information for other host processors.

Abstract: A polarity change box for selectively reversing the polarity of balanced nals and for simultaneously monitoring control and data signals while injecting a test signal. The box includes an input connector and an output connector for receiving and transmitting signals, respectively, and a plurality of circuits for transmitting balanced signals. Each circuit includes a pair of input leads from the input connector and a pair of output leads from the output connector which are electrically connected to a double pole double throw switch. Test points are electrically connected to each output lead. The switch may be selectively positioned in a "normal", "inject", or "reverse" position. In the "normal" position, the first and second input leads are electrically connected to the first and second output leads, respectively, and the output signal has the same polarity as the input signal. In the "inject" position, the switch opens the circuit allowing a test signal to be injected.

Abstract: A method is described for providing an estimate of the state of a stationary or moving contact in a three dimensional ocean. The method comprises the steps of collecting information about a location of an observer during a sequence of time, information from at least one sensor about a position of the contact relative to the observer during the time sequence, and a knowledge vector. Transforming the information into a series of three dimensional geographical grids. Examining the grids to identify hypothesized contact paths and analyzing the hypothesized contact paths to produce an estimate of the state of the contact with respect to the location of the observer. A device for providing the estimate of the state of a stationary or moving contact includes a grid stimulation block for transforming the collected information into the three dimensional geographical grids. A fusion block where grids corresponding to similar time intervals are combined or fused.

Abstract: A slotted cylinder transducer is provided having a cylindrical metal or cosite material shell. A cylindrical piezoelectric driver is bonded to the inside of the shell with an opening corresponding to the slot. The shell thickness is tapered radially about the longitudinal axis such that the thickness is a maximum 180.degree. away from the slot and decreases progressively to a minimum adjacent each side of the slot. The piezoelectric driver is reverse tapered from the shell taper in that the thickness of the driver is a minimum 180.degree. away from the slot and increases progressively to a maximum adjacent each side of the slot. This taper places a larger volume of the driver material in the slot region of the shell where the maximum radial displacements occur, thus providing higher acoustic energy levels. When used as a hydrophone to detect acoustic signals in the surrounding medium, the larger volume of material at the point of maximum displacement provides increased signal detection capability.

Abstract: A portable tracking array to be used in a system for determining the track nd/or the range of a target vehicle. The array includes a fiber optic hydrophone for acquiring acoustic signals from the target vehicle. The fiber optic hydrophone is encapsulated within a plastic material such as polyurethane. The array further includes a fiber optic cable for transmitting signals to and for receiving signals from the fiber optic hydrophone, which fiber optic cable has an end encapsulated within a termination coupling, and a length of perforated material extending between the terminal coupling and the plastic material encapsulating the fiber optic hydrophone to allow water entry and to substantially eliminate air cavities which interfere with acoustic performance.

Abstract: A system is provided for suppressing flow-induced cavitation in a fluid f. At least one acoustic transducer is coupled to the fluid flow in a region that is susceptible to the formation of cavitation bubbles. The transducer (or transducers) applies an acoustic field to the fluid flow in order to raise the cavitation threshold pressure of the fluid flow above the total local pressure including the pressure drop induced by the fluid flow and the pressure due to the acoustic field.

Abstract: The present invention comprises a bellmouth adapter assembly for deploying nd retrieving a towed array from a vessel that includes a bellmouth having a rearwardly extending tubular member with an axial centerline, and a distal first flange member extending outwardly from the tubular member, the first flange member having a first inner curved surface. The adapter has a second flange member which is concentrically superimposed over and fixed to the first flange member and has a second inner curved surface. This second curved surface is selected so that its bend radius is larger than the bend radius of the first inner curved surface.

Abstract: A system is provided for developing program test sets with test hardware conforming to well known test industry standards, such as VXI, VME and GPIB standards. The system has a computer with a display console. After initialization and password checks, the console displays a front panel from which a user chooses the instruments, switches, connections, inputs, outputs, etc. which make up the program test set. As each choice is made, the system generates test script corresponding to the choice. The system then uses the test script, or macro, to generate the graphical representation of the component and its connections on the display. The graphical displays are standardized for each functional component or operation of a program test set, as well as being standardized between program test sets. The macros further allow a program test set to be more efficiently developed by coding macros rather than by developing graphical displays.

Abstract: An SCSI controller adapted as a network file server provides a virtual coction between a plurality of host processors and a single SCSI initiator. The controller contains a removable host adapter for connection to any type of network interface. When a host processor issues a command packet and requests status information of a target device, that status information is passed to the requesting processor and subsequently stored in the controller and made available to all other host processors on the network. A fault tolerant performance monitoring algorithm, executing within the controller, is scheduled to non-intrusively and periodically check the status of each SCSI target device and to store that status information for all host processors.

Abstract: The invention provides a hydrodynamically and stealth shaped suite of antas and sensors mounted above a hydrodynamically and stealth shaped mast. The mast is configured to extend from the sail of a submerged vessel to the surface so as to provide the vessel with satellite communications capabilities. The hydrodynamic shape of the mast minimizes the surface wake and the stealth shape of the antenna suite and mast minimizes the radar cross section of the system, lessening detection by hostile forces. To obtain a stealth shape, the radar suite utilizes a conformal phased array antenna. In addition, electro-optical sensors in the antenna suite provide visual, environmental and other sensing capabilities to the system. Further, structurally embedded ESM antennas provide ESM and radar capabilities.

Abstract: A mechanical strain relief for a cable is firmly attached directly to the using of the connector to which the cable termination is plugged into. The strain relief has a split clamp aligned perpendicularly to the cable and extends from the housing sufficiently such that the clamp does not interfere with the use of a watertight rubber boot bonded to the housing to make the connector watertight. The clamp is opened and the cable is inserted into the connector. The clamp is then closed and tightened against the cable, such that any forces on the cable are transmitted through the strain relief to the housing. A guard extends from the strain relief and is shaped to loop around the cable to provide protection for the connector from foreign objects which would otherwise strike the termination or connector.

Abstract: A switch assembly and method of making same are provided. First and second eals are mounted in spaced apart relation about the elongate body of a delicate switch such as a reed switch. The resulting switch/seal assembly is inserted into a rigid housing that encases the switch and seals. The housing is in circumferential contact with each seal. The seals are spaced apart from one another to reside on either side of a port in the side of the housing so that an annular chamber is defined between the elongate body and the housing between the seals. A damping material is injected through the port to fill the annular chamber. The housing can extend past the elongate body at either end to define first and second open-ended chambers through which electrical leads extending from the elongate body pass through. The damping material can also be used to fill the first and second open-ended chambers once electrical connection to the leads is made.

Abstract: The invention provides a system for attaching one or more unmanned, hydroamically shaped, autonomous, undersea platforms to the bow of a submarine. An array of depressions, each matching the shape of the platforms, is provided in the bow of the submarine, equally spaced about the circumference of the submarine. Once seated in the depressions and attached to the submarine, the platforms provide a smooth, hydrodynamic shape to the bow of the submarine. Additionally, conformal arrays on the platforms mate with conformal arrays on the bow of the submarine to form a continuous conformal array and the platforms' weapons systems provide the submarine with forward deployed weapons when the platforms are attached. A platform is launched by detaching it from the submarine bow and raising the leading edge of the platform slightly into the water flow around the bow. Hydrodynamic forces lift the platform away from the submarine for an acoustically quiet launch.

Abstract: An antenna is provided in which electromagnetic signals in the High Frequy and Super High Frequency bands are propagated utilizing ionized gas, or plasma. Energized electrodes ionize the gas and the plasma is confined within non-metallic coaxial tubes contained within a non-metallic pressure vessel. Electric field gradients are used to change the shape and density of the plasma to affect the gain and directivity of the antenna. The inner plasma tube acts as the radiating source, while the outer plasma tube is used to change the radiation of the inner tube and to reflect the radiated signal. Instrumentation measures the density of the plasma providing a means to measure incoming signals as well as to regulate the radiation frequency.

Abstract: Apparatus for controlling cooling fans for variable electrical loads. A controller monitors cooling fan output, ambient temperature and the electrical load. The controller then matches the fan speed and resulting cooling to the existing electrical load and ambient temperature. As a consequence, fan speed is maintained at a minimum necessary to sustain appropriate cooling levels. This minimizes the generation of structureborne and airflow noise.