Abstract: A system and method are provided for launching and recovering an unmanned, water-born vehicle (UWBV) from a mother ship. The UWBV mimics the behavior of dolphins and is positioned ahead of the ship in preparation for bow riding. The UWBV uses a guidance system to position and keep in the bow wave. A high-frequency (HF) sonar transceiver array aboard the ship computes and sends course corrections to maintain the UWBV within the bow wave. The frequency range of the HF array can be 100 kHz or higher due to the short distance between the ship and the UWBV. Accordingly, the HF array can have a small aperture allowing for accurate bearing resolution. Course corrections can be sent on a near-continuous basis such that changes in thrust and rudder angle can be minimized to allow for accurate control of the UWBV.

Abstract: The invention as disclosed is an underwater based electric energy production system. A cable having a piezoelectric core is attached on one end thereof to a floating buoy and on the other end thereof to an anchor. The system is deployed in the water such that the cable extends vertically through a water column. Movement of the cable due to water current generates electric power that can be harvested and stored. The floating buoy can be at or near the water's surface and the anchor can but need not rest on the sea floor.

Abstract: A remote power delivery system includes an electrically-conductive plate disposed adjacent to a sensor system of an underwater vehicle's hull. At least one toroidal coil is disposed between the plate and the face of the sensor system exposed to water. An AC voltage is applied to the plate so that a time-harmonic voltage is induced in each toroidal coil.

Abstract: A two-stage voltage step-up converter and energy storage system is utilized for harvesting trickling electrons from benthic microbe habitats. A relatively random low voltage from the microbial fuel cell (less than about 0.8 VDC) is provided to the first stage step-up converter, which stores power in a first output storage device. A first comparator circuit turns on the second stage step-up converter to transfer energy from the first output storage device to a second output storage device. A second comparator circuit intermittently connects the load to the second output storage device. After initial start-up, the system is self-powered utilizing the first and second output devices but may use a battery for the initial start-up, after which an automatic switch can switch the battery out of the circuit.

Abstract: A transducer array assembly includes a support structure having a plurality of predetermined openings therein for accommodating transducer components. Flexible circuits are embedded in the support structure. Each flexible circuit has first ends being positioned in the support structure predetermined openings. Terminal blocks are joined to the second ends. Transducer elements are positioned in the support structure predetermined openings and placed in electrical communication with the flexible circuit first ends. A polymer material is provided surrounding the transducer elements, said support structure, and said flexible circuit first ends. There is also provided a method for manufacturing the transducer array.

Abstract: The invention as disclosed is a parallel plate antenna having a number of stacked horizontal plates and two vertical plates. Alternating ones of the horizontal plates are electrically coupled to one vertical plate such that the horizontal plates coupled to one vertical plate are interleaved with the horizontal plates coupled to the other vertical plate. The assembled antenna is mounted on a planar mounting flange. The height/width of the antenna is approximately 1/30th of a wavelength at the frequency of operation.

Abstract: Disclosed herein is a method to produce a semi-crystalline fluoro-polymer film. A semi-crystalline fluoro-polymer material is used. The material is compressed to produce the film. During compression, the material is maintained at a temperature below the melting point of the material. The compression step can be cycled to allow cooling of the material between compression stages. Alternative methods are provided for compressing the material with a co-extrusion substrate, extruding the material and utilizing mandrel expansion for the material.

Abstract: A buoyant cable antenna system includes an HF antenna section connected to an outboard end of a VLF/LF antenna. With respect to the HF antenna, the VLF/LF appears to be a standard coaxial cable so that the HF antenna can be configured as desired for HF antenna operation. The VLF/LF antenna is comprised of a segment of coaxial cable. The inboard end of the braided outer conductor of the segment of coaxial cable is connected to ground through a capacitor so that the VLF/LF signals are effectively isolated from ground. In this way, VLF/LF currents are induced on the outer braided conductor of the segment of coaxial cable to thereby operate as the VLF/LF antenna.

Abstract: The present invention provides a fixture and method for mounting a head window to a frame for use in a submarine periscope system. The fixture supports the head window during the potting of the head window to the frame. A spring-loaded clamping plate is mountable to a baseplate for relative movement therebetween. The clamping assembly has an oval recessed portion. A plurality of spaced apart feet are formed within the oval. The feet support and are bonded to the head window. Shim stock are placed between the feet to define a critical gap.

Abstract: A method for classifying data includes selecting an elemental size and features for the data that are representative of possible subclasses. Resolution widths are selected in conjunction with these features. Models associated with symbols are developed from these resolution widths and features. Data is compared with these models to give a likelihood that the model applies. The best model is determined and a signal is provided related to the symbol associated with the best model.

Abstract: A transducer with a closed heat pipe is provided with a hot surface and a cold surface. The hot surface is in contact with the transducer interior and the cold surface is in contact with a cooler contact area. A fluid is used in the pipe which boils at the temperature of the hot surface and condenses at the temperature of the cold surface. A wick inside the heat pipe facilities the return by capillary action of the condensed fluid to the hot end. The heat pipe can be evacuated to adjust the boiling temperature of the fluid. A variant involves drilling additional holes into ceramic rings and inserting heat pipes. Increasing the heat pipe length into the tail mass and the piston increases the cool region for the fluid to condense; thereby improving the performance of the transducer.

Abstract: A method is provided for calculating a class-specific iterated subspace for a classification system utilized in a computing system. Training data in the specific class for the class-specific iterated subspace is collected. A linear orthogonal transform is applied transforming the data into at least one bin. Magnitude squared bins are calculated and used as columns of a matrix. Orthonormal vectors of this matrix are selected and a J function is calculated. The J function and orthonormal starting vectors are used to obtain the class-specific iterated subspace for each class. The method further applies these class-specific iterated subspaces in a classification system for determining the most likely class of a data signal of interest.

Abstract: The invention as disclosed is a non-contact method and apparatus for continuously monitoring a physiological event in a human or animal, such as blood pressure, which involves utilizing a laser-based interferometer system in combination with a laser tracking system and a signal processor to produce a waveform that is representative of a continuous physiological event such as blood pressure or respiration in a subject.

Abstract: A subsurface deployable antenna array is provided which expands upon deployment and contracts for storage to provide an antenna array that can be stored in a comparatively compact space. Electronically interconnected antenna modules are connected by expandable/contractable connectors. A helically-organized bundle of optical cables and electrical wiring are utilized in the expandable/contractable connectors. Mechanical, electrical, or hydraulic means may be utilized to control the spacing between the antenna modules.

Abstract: A disposable sensor device for remote sensing of conditions such as temperature and dangerous gasses includes a body defining an enclosed chamber, a power source mounted in the chamber, an on-off switch mounted on and accessible from outside the body, a processor mounted in the chamber and powered by the power source, sensors mounted on the exterior of the body in communication with the processor and capable of detecting gasses and temperature. A transceiver, a speaker, and a microphone are mounted in the chamber and in communication with the processor. The transceiver is adapted to receive sound signals from a remote unit and input the signals to the speaker for broadcast, and the microphone is adapted to receive sound signals from outside the body and input the received sound signals to the processor for transmittal to the remote unit.

Abstract: The invention as disclosed is a strain sensor that locates and quantifies the strain energy from a structure. The strain sensor has a lead zirconate titanate wafer with a circular shape such that the shape does not directionally restrict the signal of the sensor.

Abstract: A semiclosed diesel fueled Brayton cycle power system is provided using CO2 and steam as the working fluid. Combustion occurs in a combustor between diesel fuel and O2 with CO2 present as a diluent. During combustion, a heated, high pressure working fluid of CO2 and steam is formed. The heated working fluid is expanded in a turbine and power is withdrawn from the fluid. The fluid is then used in a regenerator to heat cooler, compressed CO2 before the compressed CO2 is transferred to the combustor. The expanded working fluid is cooled conventionally by seawater in a cooler, condensing steam in the working fluid to water. The water is separated from the gaseous CO2. The gaseous CO2 is recycled, and the water is used to backfill the system's diesel fuel tank.

Abstract: The invention as disclosed is a fiber optic interferometric directional acoustic density sensor that increases the directionality of a vector sensor that is much smaller in size than the wave length of an acoustic wave. This is accomplished through the use of second order directionality by measuring the acoustic fluctuations of fluid density at a point, wherein the acoustic density fluctuations are determined according to the principles of fluid compressibility and conservation of mass using a density fluctuation measuring apparatus that restricts two of the three vector components of the particle velocity of the acoustic wave and that employs a laser interferometer to measure the fluid density fluctuation along the remaining vector component.

Abstract: A water entry system increases the drag of an underwater vehicle by disrupting the cavity that forms during high-speed transit of the vehicle through the water. A series of inlet ports are positioned in regions of the vehicle where pressure stagnation occurs during transit. Flow passages connect these inlets to outlet ports at regions of lower pressure. Pressure differences cause jets to flow in the respective passages. The jets produce a high flow rate normal to the original cavity boundary. The jets serve to increase drag in at least two manners. In one case, a flow jet normal to the cavity interface broadens the cavity to increase drag and slow the vehicle. In a second case, a jet can cause waves on the cavity interface to break down the stable cavity. As a result, the vehicle surface is wetted, producing skin friction drag and slowing vehicle.

Abstract: The invention as disclosed is of a method to authenticate identify and trace sonar transmissions and echoes by embedding transparent, secure and robust digital watermarks in signal space, where the additional information incurs no cost in bandwidth. The complex short time Fourier transform is selected as the domain for embedding the digital watermark, secured by a secret key, in the time frequency representation of the signal. The watermark is designed through an iterative optimization step. This step insures that the watermarked sonar is also realizable. Selection of the time frequency region for watermarking is driven by avoidance of interference with the sonar itself, or in case of network operation, other watermarks. In addition, the selected time-frequency region remains robust to sound channel and other transmission effects. Sonar echoes are authenticated in the time-frequency plane by a correlation receiver tuned to the watermarked region using the secret key.