Abstract: A method and device to neutralize influence mines has a control module to generate signals representative of acoustic and magnetic signatures of a ship. These representative signals will either detonate the threat mines or ensure that transiting ships will not set off the mines. An acoustic transducer array is coupled to the module to transmit acoustic signals representative of the acoustic portion of the signatures. A magnetic signal transmitter is coupled to the module to transmit magnetic signals representative of the magnetic portion of the signatures. An anchor is connected to the module, acoustic array, and magnetic signal transmitter to hold them at the ocean bottom, and a buoy is connected to the module, acoustic transducer array, and magnetic signal transmitter to hold the device vertically.

Abstract: A bottom activated retractable control device includes a fin member having a front edge, a trailing edge opposite to the front edge, a bottom edge between the front edge and the trailing edge, and an arm portion extending from and coextensive with the leading edge and away from the bottom edge. The arm portion includes a pivot pin extending in a perpendicular direction from each side of the arm portion. A pivot housing having an aperture is provided for receiving the pivot pin of the arm portion, the housing enabling both a vertical pivot of the fin member upon contact of the fin with, an object and axial rotation of the fin about the arm portion of the fin member. A well is formed in the bottom surface of an underwater vehicle corresponds in depth to a fully retracted position of the fin member and in width to any rotated position of the fin member.

Abstract: A flow meter strut assembly includes a strut portion having a first end plate, a second end plate, a longitudinally adjustable flow meter support structure between.the first and second end plates, and curved mounting surfaces formed on outer surfaces of each of the first and second end plates of the strut portion. At least one flow meter is adjustably mounted on the flow meter support structure. The flow meter support structure is adjustable longitudinally by a turnbuckle assembly connected between the flow meter support structure and the second end plate.

Abstract: A non-chromate conversion coating and method of applying same wherein the coating comprises a titanate, such as potassium titanate or sodium metatitanate, as a “drop-in replacement” for a chromate in an otherwise chromate-containing conversion coating.

Abstract: An apparatus for determining the velocity of sound waves which includes a liquid medium having a plurality of gas bubbles. In the liquid medium, a laser transmits a light pulse to interact with the bubbles excited by the sound wave. Backscattered light from the interaction of the light pulse is received. A processor is then responsive to the detector to provide detection of the acoustic wave through the fluid medium.

Abstract: A manufacturing process is provided to increase fracture toughness and reduce brittleness for a semi-crystalline polymer material. A material such as poly(vinylidene fluoride-trifluorethylene) or p(VDF-TrFE) is placed in an inert oxygen-free atmosphere and heated to a temperature that is greater than room temperature but below the melting temperature of the material. The material is then irradiated with beta particles until a desired level of fracture toughness is achieved where fracture toughness is a function of the radiation dose.

Abstract: A neural director is provided which is a neural network constructed with weights that are determined a priori. The neural director receives an input vector X comprising “I” input components “Xi” and generates in response an output vector Y comprising “J” output components. The neural director has an input processing node layer which receives the input vector X and an output processing node layer which generates the output vector Y. The connections between the input and output processing node layers are a unique weighting set w(i,j) that contains an internal representation of a uniform spatial distribution of “J” unit vectors throughout a unit sphere of “I” dimensions. Thus the cosine value between any two adjacent unit vectors is a constant everywhere in the unit sphere.

Abstract: The apparatus and method of the present invention utilize hysteresis to provide accurate and stable track quality indicator (TQI) data. In accordance with the present invention, each TQI state has two corresponding thresholds. Specifically, each TQI state has an initial threshold that must be surpassed by an initial or first summed log likelihood ratio (SLLR0) before a change in current TQI state is made to a higher TQI state, and a lower threshold below which a second SLLR1 must decrease in order to effect a change in current TQI state to a lower TQI state. Thus, SLLR0 is used to determine if the tracker quality indicates a low SNR track, an uncertain track or a lost track, and SLLR1 is used to determine if the tracker quality indicates a strong track. In accordance with the present invention, the values of SLLR0 and SLLR1 and the absolute value of the smoothed tracker residual are used to generate a current TQI value.

Abstract: A method for coupling fiber optic elements includes providing a hollow wax housing. A first fiber optic element is inserted in a first direction into the housing to position a free end thereof in the housing. A second fiber optic element is inserted into the housing from an opposite direction to position a free end of the second fiber optic element in the housing confronting the first fiber optic element free end. The housing is filled with optical grade epoxy resin which is permitted to cure, thereby to effect physical and optical connection between the first and second fiber optic elements. The free ends are in close proximity, or in the case of coupling from one strand to many, in enough of a spaced relation to cause needed light diffusion.

Abstract: A system for bearinqs-only contact state estimation in response to target bearing and ownship speed and course information provided for a plurality of observation legs at successive points in time, includes a plurality of neural networks and a data fusion circuit. Each of the neural networks generates range-normalized parameter estimate information for one of the observation legs in response to target bearing and ownship speed and course information for an associated one of the observation legs, provided thereto at each point in time and information generated for the previous point in time. The data fusion system receives the range-normalized parameter estimate information from the neural networks and generates the contact state estimate in response thereto.

Abstract: A method for estimating the real and imaginary Young's modulus, shear modulus and Poisson's ratio of a specimen at an excitation frequency. The specimen is first joined to a reciprocating test apparatus at one end with a mass positioned at the other end. The test apparatus reciprocates at the excitation frequency and accelerations are recorded at each end of the specimen. The Young's modulus is calculated from the recorded accelerations. The specimen is then joined to a reciprocating rotational test apparatus at one end with a rotational inertial mass positioned at the other end. Accelerations are recorded upon subjecting the specimen to rotational reciprocations at the excitation frequency. The shear modulus is calculated from these accelerations. Poisson's ration can be calculated from the Young's modulus and the shear modulus at the excitation frequency. All of the calculations may be performed giving both real and imaginary values.

Abstract: A system and method is disclosed for retrieving an untethered submarine tube-retrievable UUV in which the untethered submarine tube-retrievable UUV may be retrieved through the torpedo tube of a submarine. The untethered submarine tube-retrievable UUV has a capture cable extending therefrom with a transducer to produce a homing signal. A tethered homing signal seeking UUV is guided toward the homing signal. Capture arms on the tethered homing signal seeking UUV engage the capture cable and guide the capture cable to one of several cable snagging eye-members. The winching cable is then winched back into the torpedo tube thereby drawing the untethered submarine tube-retrievable UUV into the torpedo tube.

Abstract: A signal processing system provides and processes a digital signal, converted from to an analog signal, which includes a noise component and possibly also an information component comprising small samples representing four mutually orthogonal items of measurement information representable as a sample point in a symbolic Cartesian four-dimensional spatial reference system. An information processing sub-system receives said digital signal and processes it to extract the information component. A noise likelihood determination sub-system receives the digital signal and generates a random noise assessment of whether or not the digital signal comprises solely random noise, and if not, generates an assessment of degree-of-randomness. The information processing system is illustrated as combat control equipment for undersea warfare, which utilizes a sonar signal produced by a towed linear transducer array, and whose mode operation employs four mutually orthogonal items of measurement information.

Abstract: A missile launch assembly for underwater vehicles includes a launch tank having mounted therein an expandable elastomeric disc and a turbine, a water inlet conduit, an impulse tank interconnecting the water inlet conduit and a missile launch tube, and a pump inducer mounted in the water inlet conduit and drivable by the turbine. Movement of the disc from an expanded to a non-expanded condition causes water in the launch tank to drive the turbine to drive the pump inducer to pump water from the water inlet conduit to the impulse tank and thence to the launch tube to effect launch of a missile therein.

Abstract: A neural sensor is provided which receives raw input data defining a pattern, such as image or sound data, and generates a classification identifier for the pattern. The neural sensor has a pattern array former which organizes the raw input data into the proper array format. A first order processing section receives the pattern array and generates a first order feature vector illustrative of first order features of the input data. A second order processing section also receives the pattern array and generates at least one second order feature vector illustrative of gradients in the input data. A vector fusion section receives the feature vectors from the first and second order processing sections and generates a single fused feature vector which is provided to a pattern classifier network. The pattern classifier network, in turn, generates a pattern classification for the input data.

Abstract: A system for digitally demodulating optical hydrophone signals is provided. The system includes an optical hydrophone connected to an analog-to-digital converter and further connected to a digital signal processor. Within the digital signal processor, a demodulator is calibrated by a preferred automatic calibration circuit such that mixer frequencies are coherently mixed with the incoming acoustic signals received by the hydrophone. The automatic calibration circuit preferably determines an extreme case of phase offset by following a programmable routine including a series of tests. After the extreme case is detected, the precise phase calibration is known and provided to the demodulator mixer tables. The automatic calibration circuit can be utilized for automatic calibrations of multisensor systems containing large numbers of hydrophones.

Abstract: A method is disclosed for protecting optical fibers embedded in the armor of a tow cable. The method includes the steps of winding a resin-impregnated fiber onto a stainless steel tube, and curing the resin to form a hard protective filament shell around the stainless steel tube. The fiber is a continuous fiber and the step of impregnating is either in combination with the step of winding or prior to the step of winding. The fiber used is any one of a carbon fiber, a Kevlar™ fiber, a boron fiber or the like. The winding is either applied during formation of the steel tube or subsequent to formation of the steel tube. The method further comprises the step of winding galvanized steel armor wires of a predetermined diameter around the tow cable core to form the tow cable and helixing the protected tube amongst the galvanized steel armor wires.

Abstract: A system and method are provided for an adaptive filter that is especially useful for sonar signal processing. The beam outputs of a conventional beamformer are provided as inputs to adaptive notch filters in accord with the present invention. The outputs of the plurality of adaptive notch filters are applied to a standard cross correlation process. In each of the adaptive notch filters, the beam outputs are split into two paths and in one path are applied directly to a signal combiner. In the second path, the beam outputs are delayed. The delayed beam outputs are applied to an adaptive finite impulse response filter, the output of which is an estimate of the narrowband interference contained within the beam output. The narrowband interference is then suppressed in the signal combiner prior to application to the standard cross correlation process.

Abstract: An apparatus for controlling fluid pressure recovery includes an elongated housing having an opening at a first end thereof, an opening at a second end thereof, an inner peripheral surface, and a fluid flow passageway therethrough. The apparatus further includes a plurality of choke members fixed to the inner peripheral surface of the housing, each of the plurality of choke members being spaced from an adjacent choke member and projecting a predetermined distance into the fluid flow passageway of the longitudinal housing. The plurality of choke members sequentially produce a reduced turbulent free shear fluid layer from the first end to the second end of the elongated housing.

Abstract: An isolated mechanical fastening system, which includes an exterior first section having a first transverse bore. The system also includes an exterior second section having a second transverse bore, wherein the second transverse bore is aligned with the first transverse bore. There is also an interior third section having a third transverse aperture. This third section is interposed between the first section and the second section and the third transverse bore is aligned with the first and second transverse bores. A fastener is positioned in the first, second and third transverse bore and is fixed to the first section. A polymeric material is positioned in the third section between the fastener and the peripheral wall of the third section.