Abstract: The present invention relates to a fiber optic sensing device having utility as a roll sensor and/or a pitch sensor. The sensing device comprises at least one optical fiber supported in a structure, a movable mass supported within the structure, and at least one detector for detecting changes in tension in the at least one optical fiber due to movement of the movable mass. In the sensor of the present invention, the optical fiber(s) are the only deformable structures, thus maximizing sensitivity.

Abstract: A mounting bracket for removably connecting an acoustic sensor element to an inside wall of a sonar dome of a marine vessel includes a first protrusion bonded at a first end thereof to the inside wall of the sonar dome, extending inwardly therefrom, and provided with a first widthwise extending slot proximate, but spaced from, the inside wall, and a second protrusion bonded at a first end to the sonar dome inside wall and extending generally parallel to and spaced from the first protrusion, the second protrusion being provided with a widthwise extending second slot in a side thereof, the second slot being opposed to and in alignment with the first slot. The slots are adapted to receive portions of the acoustic sensor element and to hold the acoustic sensor element in a position proximate to and removed from the inside wall of the sonar dome.

Abstract: A method and apparatus to clear mines uses tag particles dropped into ambient water across a wide area by an aircraft to sink and stick to submerged mines. The tag particles each contain a gas volume dimensioned to resonate with impinging acoustic energy and reflect portions of the impinging acoustic energy from a targeted mine. An unmanned underwater vehicle platform having a sonar system provided with at least one transducer projects the acoustic energy through the ambient water. At least one hydrophone transducer in the sonar system receives the reflected portions of the projected acoustic energy to locate a targeted mine to enable its destruction by high-energy supercavitating projectiles fired from the platform. Tag particles dissolve after a period of time to provide virtually no discernable traces of a mine hunting operation.

Abstract: A color sensor for generating color information defining colors of an image includes an input section, a color processing section, a color comparison section, a color boundary processing section and a memory processing section. The input section includes an array of transducer pairs, each pair defining one of a plurality of pixels. Each transducer pair generates two peak outputs, one for the selected color of each transducer of the pair. A plurality of pixel processors in the color processing section each receives the outputs from one of the transducer pairs. The color processing section generates a color feature vector representative of the brightness of the light incident on the pixels and a color value corresponding to the ratio of outputs from the transducers comprising the transducer pair associated with the pixels. The color boundary processing section generates a plurality of color boundary feature vectors, each representing the difference between the color value for a pixel and its neighboring pixels.

Abstract: A spreader arm aperture generation system for use with a towed array is provided. The spreader arm aperture generation system broadly comprises a plurality of lines and a plurality of hydraulically activated, inflatable tubes for generating horizontal and vertical separation among the lines. Each of the tubes is filled with seawater to a desired pressure to achieve the desired horizontal and vertical line separation. Preferably, each of the tubes is formed from a high strength woven fabric.

Abstract: A high speed paddle wheel catamaran includes a hull configuration having a main hull portion with at least one defined cavity area in a lower surface of the main hull and opposing side pontoons depending from the main hull portion. The depending side pontoons correspond in orientation to a longitudinal axis of the catamaran. A paddle wheel assembly for the vessel includes a rotatable cage hub mounted on each pontoon. A plurality of vane members are rotatably mounted between the opposing cage hubs and adjacent an outer perimeter thereof. Each vane member is selectively rotated to one of a lift or thrust position according to an arcuate location of the vane as it passes through the water.

Abstract: A high-speed supercavitating underwater vehicle includes an elongated hull of circular cross section, the hull having a cavitator at a forward end thereof and means for ventilating gas to form a cavity around the hull in underwater travel. An expandable annular skirt is fixed on the hull and is provided with an outer surface proximate an outer surface of the hull. The skirt is expandable to increase a diameter of the skirt from proximate a diameter of the hull to proximate a diameter of the cavity to define an annular gas film between the expanded skirt and a boundary of the cavity. The expanded skirt acts to substantially reduce the flow of gas from a forward high pressure zone of gas to an after low pressure zone of gas.

Abstract: The present invention relates to a method of producing an electrocatalytic cathode for use in an electrochemical cell system comprising the steps of providing a carbon substrate and simultaneously depositing palladium and iridium on the carbon substrate by cyclic voltammetry or by controlled potential coulometry. The simultaneous deposition of the palladium and iridium is preferably carried out using a solution containing 1.0 mM palladium chloride, 2.0 mM sodium hexachloroiridate, 0.2M potassium chloride, and 0.1M hydrochloric acid.

Abstract: An additive for an aluminum-based semi-fuel cell system includes a combination of components including gallium, oxygen, and a sodium component dissolvable an alkaline electrolyte solution such as seawater and sodium hydroxide. These components form sodium gallium oxide and prevent or reduce formation of an oxide layer on a surface of an aluminum anode in the alkaline electrolyte of the semi-fuel cell system.

Abstract: A control surface system is particularly well suited to provide improved control for undersea vehicles having integrated motor propulsors (IMP). The control surface system is deployable beyond lateral peripheral dimensions of the IMP and undersea vehicle. A plurality of arc-shaped control elements is disposed in a stowed position in an annular intake recess inside of an annular duct on the undersea vehicle. Struts connect each of the control elements to the annular duct. A deployment device rotates each of the control elements and the struts radially outwardly beyond lateral peripheral dimensions of the vehicle to a fully deployed position. A latching mechanism selectively engages and disengages the struts to hold the control elements in the stowed position and the fully deployed position, respectively. Launch tubes sized for the undersea vehicles can launch undersea vehicles provided with control surface system.

Abstract: A method and apparatus are presented for determining turbulent boundary layer thickness. In this method and apparatus, a pair of sensors are mounted to a solid surface interfacing with a fluid at two separate stream wise locations. A voltage output from the pair of sensors is recorded and a real non-dimensional value of a correlation coefficient is computed with measured data from the recorded voltage. A laboratory non-dimensional value of the correlation coefficient is independently determined from laboratory data. The real non-dimensional value is compared with the laboratory non-dimensional value to obtain a boundary layer thickness having a value which minimizes a difference between the values of the real non-dimensional value and the laboratory non-dimensional value.

Abstract: A static memory processor for pattern recognition and an input data dimensionality reduction is provided having a multi-layer harmonic neural network and a classifier network. The multi-layer harmonic neural network receives a fused feature vector of the pattern to be recognized from a neural sensor and generates output vectors which aid in discrimination between similar patterns. The fused feature vector and each output vector are separately provided to corresponding positional king of the mountain (PKOM) circuits within the classifier network. Each PKOM circuit generates a positional output vector with only the element corresponding to the element of the fused feature vector or output vector having the highest contribution in its respective vector having a value corresponding to one. The positional output vectors are active in a multidimensional memory space and are read by a recognition vector array which generates class likelihood outputs determined by the occupied memory space.

Abstract: A heat exchange tube includes a tubular conduit for flowing a working fluid therethrough and for conducting heat between the working fluid and a thermal field proximate the tube, and a wire extending axially through the tubular conduit and spaced from an inside surface of the tubular conduit. The invention also provides a method for increasing heat transfer about a tubular conduit by positioning a wire in the conduit.

Abstract: The present invention relates to a system for sensing the curvature of a towed hydrophone array and a curvature sensor used in the system. The system has at least two curvature sensors positioned along the length of the array. Each of the curvature sensors comprises a bend member which bends as the array bends, at least one optical fiber within the bend member, and at least one detection device embedded within the at least one optical fiber to detect a change in the strain in the at least one optical fiber.

Abstract: The calibration circuit is used with a differential input, monolithic integrated circuit preamplifier in a sensor system. The calibration circuit tests the integrity of the sensor, the preamplifier, and the wiring in the sensor system. The calibration circuit includes first and second calibration capacitors having different capacitances connected to the preamplifier input leads. A calibration signal source is connected between the capacitors. The capacitors are preferably implemented on the same integrated circuit as the preamplifier. In operation, a calibration signal of known amplitude is applied to the calibration circuit and the level at the preamplifier output is determined. The level at the preamplifier output indicates certain conditions relating to the integrity of the sensor and its wiring, for example, an open circuit condition or a short circuit condition.

Abstract: A system and method for a neural network is disclosed that is trained to recognize noise characteristics or other types of interference and to determine when an input waveform deviates from learned noise characteristics. A plurality of neural networks is preferably provided, which each receives a plurality of samples of intervals or windows of the input waveform. Each of the neural networks produces an output based on whether an anomaly is detected with respect to the noise, which the neural network is trained to detect. The plurality of outputs of the neural networks is preferably applied to a decision aid for deciding whether the input waveform contains a non-noise component. The decision aid may include a database, a computational section and a decision module. The system and method may provide a preliminary processing of the input waveform and is used to recognize the particular noise rather than a non-noise signal.

Abstract: The present invention relates to a fiber optic rotation sensing device. The sensing device includes a stationary base, a rotatable member, and an optical fiber configured in at least one loop about the rotatable member. The optical fiber is secured to an exterior portion of the rotatable member and to the base. Rotation of the rotatable member causes a distortion of the at least one loop and a change in the intensity of the light passing through the optical fiber. The change in light intensity is measured to provide an indication of the degree of twist of the rotatable member.

Abstract: A sonar system and method are provided to extract and identify information about a particular target illuminated by an active sonar system. The present invention utilizes a Volterra Series Expansion in conjunction with a least squares procedure to estimate channel and target responses, which may be linear or nonlinear. The system estimates the channel and target responses for different orders of the Volterra Series Expansion and then selects the order for which a minimum error is determined with respect to a measured acoustic return signal. The system requires as inputs only the excitation waveform and the measured acoustic return signal.

Abstract: A water tight shell joint for a super cavitating underwater vehicle is described. The shell joint includes a female member defining a first part of at least one slot for ejecting gas, a male member defining a second part of the at least one gas ejection slot, and at least one shim for adjusting the width of the at least one slot to obtain a volume of ejected gas sufficient to obtain a uniform cavity about the vehicle.

Abstract: An underwater acoustic transducer includes a set of formed substrates of piezoelectric polymer composite, the formed substrates having at least a first and second surface. Conductive electrodes are deposited on the first and second sides of the formed substrates. One surface of the substrate is bonded to an acoustically absorptive backing material. Either surface can be made to conform to a singly or doubly curved geometry. Electrodes deposited on these substrates may be continuous to form a single transducer element, or segmented to form sub-arrays of transducer elements.