Abstract: The invention described herein relates to an antenna system which makes use of the waveguide properties of sea ice. The antenna system broadly includes at least one antenna wire extending along and preferably in contact with a sea ice surface for transmitting and receiving substantially vertically polarized radio waves. In a first embodiment, the antenna system has a single antenna wire connected to a tuner at one end and grounded to seawater at a second end. The antenna system also has a second length of wire attached to the tuner. The second wire passes through a hole in the sea ice and is also grounded to the seawater beneath the sea ice. In an alternative embodiment, only the second wire is grounded to the seawater beneath the sea ice. The single antenna wire in this embodiment is ungrounded. In yet another embodiment, the antenna system comprises a dipole antenna wire laying on the surface of the sea ice and being connected to a radio for transmitting and receiving radio signals.

Abstract: An apparatus for providing a rapid fluid impulse which can be used for launching vehicles into a liquid medium. The apparatus comprises a ring diaphragm of coupled concentric elastomeric rings, adapted to accept pressurized fluid at an interior side. The pressurized fluid extends the elastomeric rings of the ring diaphragm, placing them in shear strain. When the fluid is released, a kinetic impulse is provided and the ring diaphragm returns to its resting position. The apparatus further comprises a central check valve on the ring diaphragm. The check valve allows fluid to flow from an exterior side, through the ring diaphragm, to the interior side when exterior fluid pressure exceeds interior pressure. The invention is useful in a submarine vehicle launch assembly wherein the ring diaphragm is a component thereof.

Abstract: A system for determining the sound velocity profile in a medium, such as water, includes an acoustic signal transmitting system at a transmitting location and an acoustic signal receiving and processing system at a receiving location. In one example, the acoustic signal receiving and processing system is located in a submarine or other similar vessel, and the acoustic signal transmitting system is located in an expendable vehicle or probe that moves throughout the water surrounding the submarine or vessel. At one or more transmission times and transmitting locations, the acoustic signal transmitting system transmits an acoustic signal. The acoustic signal receiving and processing system receives each acoustic signal at an arrival time and determines the sound velocity in the water between the transmitting location and the receiving location using the arrival time, the predetermined transmission time, and the predetermined transmitting location.

Abstract: Gas bubbles in a moving fluid are collected in a chamber alongside the conduit carrying the fluid. In a preferred embodiment, an ultrasonic transducer cooperates with a reflector to create a standing ultrasonic wave pattern that is oriented at an acute angle to the horizontal axis of fluid flow. Bubbles gather at the troughs between the waves and then move between the pressure waves in the downstream direction to be collected in the chamber. Bouyant forces aid the movement of the bubbles in an upward direction. A gas permeable window at the top of the chamber allows removal of the collected bubbles.

Abstract: A system and method for operating a cylindrical acoustic projector is provided which allows efficient operation of the projector over a wide bandwidth. The system and method use multiple power amplifiers each tuned to operate over separate and narrow bandwidths, the number of seperate bandwidths corresponding to the number of amplifiers such that the total bandwidth is covered. Each tuning network assembly includes the power amplifier, a transformer and a tuning inductor, with the tuning inductor selected for proper tuning over the frequency bands the amplifier is to operate at. The narrow bandwidths for each power amplifier result in a substantial reduction in the reactive power dissipated in the amplifiers and also the total power consumption of the acoustic projector.

Abstract: The present invention relates to a method and a system for determining a weapon firing strategy for an evading target. The method of the present invention comprises the steps of sensing the motion of the target, analyzing the motion of the target, providing a weapon employment decision aid, determining the evasion region for the target using the weapon employment decision aid and the analyzed motion, visually displaying the evasion region, feeding operator knowledge about the evading target, and generating a representation of the probability of the location of the evading target. The weapon employment decision aid utilizes beta density functions to determine the evasion region. The weapon employment decision aid displays target course and speed in the form of bar graphs and allows the operator to input information about target evasion course and speed and uncertainty levels.

Abstract: A submarine antenna assembly comprises a tubular body having a removable end cap, a mast stowable in the body and extendible therefrom and having elements mounted thereon, a penetrator stowable in the body and movable therefrom by the mast upon removal of the end cap, the penetrator being adapted to bore through an ice layer, and an inflatable ring stowable in the body and movable therefrom by the mast upon the removal of the end cap. First and second capsules are in the body for retaining and releasing gas, the first capsule being adapted upon opening thereof to pressurize the body to blow off the end cap to permit movement of the mast, the ring, and penetrator out of body, and the second capsule being adapted to inflate the ring to hold the penetrator in engagement with an undersurface of the ice layer. An electronics assembly is disposed in the body and includes message retention and transmitting means in communication with the mast, and timer means in communication with the capsules.

Abstract: In accordance with the present invention, a photon transducer system is provided for obtaining information on acoustic signals within a fluid environment. The photon transducer system uses a laser-based Doppler interferometer located within a pressure release surface. The pressure release surface is formed by generating a gas pocket in the fluid, creating a boundary layer between the laser light source and the surrounding fluid. Laser light is reflected from the boundary and is detected by the interferometer to obtain the Doppler velocity of the pressure release surface. The pressure incident on the boundary can be determined from the measured velocity, providing information on the incident acoustic pressure.

Abstract: A pressure vessel insert comprises a plate having an outboard surface and an inboard surface interconnected by outer edge surfaces, and defining an aperture extending therethrough from the outboard surface to the inboard surface. The plate is provided with a modulus of elasticity within about 30% of a first modulus of elasticity of inboard and outboard skins of a wall portion of the pressure vessel shell around an opening in which the insert is disposed, in directions through the thickness of the skins.

Abstract: A device for noninvasively measuring energy emissions in the human chest. This device includes first and second spaced longitudinal flexible supports. At least one transverse support means extends between the said first and second spaced longitudinal supports. A plurality of sensor means positioned in a spaced transverse array on the transverse support. This device is an array based measurement system that minimizes the effect of rib interaction on the space-time field of the human thorax. This array-based measurement system is noninvasive so there is almost no patient risk.

Abstract: A device and method, which progressively and sequentially increases the volume of the alarm signal upon the initiation of the alarm, is provided. The disclosed device includes a multiple voltage-controlled oscillator, at least two dual-input positive-NAND gates, a shift register and a plurality of transistors and resistors, which are configured to sequentially include the resistors into the alarm circuit. The method includes sequentially and progressively increasing the volume of an initiated audio alarm signal by sequentially including one of the plurality of resistors into the alarm circuit to vary the volume of the alarm signal emanating from an alarm speaker. The resistors are included into the alarm circuit by sequentially switching on the corresponding one of the plurality of transistors. The transistors are switched on in response to outputs received from a shift register, which is shifted in response to an output received from a first NAND gate.

Abstract: A multi-function radio frequency (RF) signal warning system detects different types of RF signals, such as radar signals, provided in various RF bands and provides an indication of the type of radar signal and the RF band. The system detects pulsed radar signals having different pulse repetition frequency (PRF) ranges as well as high duty cycle radar signals and continuous wave radar signals. The system includes a receiver processor that detects the radar signals, video amplifies the radar signals with baseline correction, and processes the radar signals to determine the type of radar signal, e.g., the RF band and PRF range. The receiver processor generates audio and visual control signals and transmits the control signals to one or more remote units. The remote units receive the audio control signals and generate an audible alarm.

Abstract: A plasma antenna with a plasma column is provided. Lasers are disposed to transmit photon beams through the plasma in an alternating, oppositely directed fashion. When a laser is energized, its laser beam produces photon-electron collisions that impart momentum to electrons in the plasma. Alternating the operation of the lasers produces an alternating current in the plasma that radiates an electromagnetic field.

Abstract: A marine vehicle having enhanced maneuverability, which has a hull at least partially submerged in water. The vehicle has a forward bow, a longitudl axis extending rearwardly from said bow and opposed first and second sides. The first and second sides have respectively a first major opening and a first small opening and a second major opening and a second small opening. The small openings are positioned rearwardly of the first small opening. A major water conducting tunnel extending generally transversely through the hull from the first major opening on the first side of the hull to the second major opening on the said side of the hull. There is a propeller for causing water to flow through the tunnel. A small water conducting system extends between the first small opening on the first side of the hull to the second small opening on the second side of the hull.

Abstract: A low voltage power system for a towed active array sonar is provided. The ow voltage power system includes a shipside power supply driving a step-up transformer which is connected to the tow cable transmission line. The transmission line is connected to a second step-up transformer which provides the signal voltage to the active transducer. The transducer signal voltage is also used to drive a rectifier and DC power supply which provides DC bias voltage to the transducer. The DC voltage is isolated from the tow cable by a blocking capacitor.

Abstract: The present invention relates to a system and a method for launching an anautical vehicle from a submerged platform such as a submarine. The system includes a buoy configured to be deployed from a launching tube onboard the submerged platform, which buoy contains the aeronautical vehicle to be launched. The system further includes a gas generator for creating a pressure force which causes the buoy with the encapsulated aeronautical vehicle to be deployed from the launch platform. Once deployed, the buoy inflates a buoyancy device for putting the buoy in a partially submerged position and damping plates for resisting vertical movement of the buoy and wave motion. The buoy has a ballast arrangement for maintaining it in a substantially vertical orientation. The buoy further has an antenna for receiving commands to launch the aeronautical vehicle.

Abstract: The present invention relates to a removable air mandrel for use in manufuring towed sonar arrays. The removable air mandrel is used to position hydrophone mandrels and has an inflatable tubular structure which includes expansion limiters. The expansion limiters are preferably fibers incorporated into the tubular structure. A process for using the removable air mandrel to assemble a towed sonar array is also disclosed.

Abstract: A beam rider guidance system for directing a steerable object, such as a pedo, using a limited set of discrete guidance commands. The guidance system senses a guidance point distance representing the guidance point position relative to a bearing line to a target and the rate of change of distance between the bearing line and the torpedo. Two corresponding input functions are classified into first and second sensed linguistic variables based upon membership functions from first and second different sensed variable membership function sets to become fuzzy inputs that produce fuzzy output control membership functions from a control output membership function set based upon the logical manipulation of the fuzzy inputs. These fuzzy output functions are in the form of spikes and are converted into one of a plurality of predetermined discrete commands. A tactical limiter unit selectively defines a series of situations in which commands are allowed or not allowed to reach the torpedo.

Abstract: A system for equalizing buoyancy of a submersible vehicle. The buoyancy elization system includes a submersible vehicle having a plurality of releasable objects. Ballast release means are positioned on the submersible vehicle, and a plurality of ballast vessels are joined to said submersible vehicle by the ballast release means. One ballast vessel is released upon release of one of said releasable objects in order to equalize buoyancy.

Abstract: A power envelope shaping device for joining to a serial control output is sclosed. Multiple power switcher modules are joined to a plurality of incremental power sources and controlled by the power select circuitry module. In this way, each power switcher module can provide power from at least one of the incremental power sources on command from said power select circuitry module. The power switcher module outputs are joined together in order for providing varying power levels in accordance with a preprogrammed power envelope shape.