USA As Represented by Secretary of the Navy

Lynn T Antonelli

Fletcher A Blackmon

Lee E Estes

Kenneth M Walsh

Patrick J Monahan

Gilbert Fain

Candida L Desjardins

Francis J O'Brien, Jr

Thomas A Frank

Peter Finkel

Nathan Johnnie

Stephen C Butler

Benoit G Gauthier

Margo Staruch

Anthony J Kalinowski

William J Ohley

Jackeline D Diapis

John F Lomba

Armando M Simao

Donald I Woodward

Extendable air-based line arrays of directional projectors are provided with the arrays affixed and parallel to a ship hull. An anchor and a vibration isolator are affixed to the hull and the arrays in which the anchor and isolator separate the arrays from the hull. Each of hydraulically-actuated arms rotatably connect at a cam to an arm stop affixed to the anchor. A sound vibration dampener is positioned between the arm stops. The arms are capable of extending the directional projectors to an activation position with the projectors forming narrow beams into the water to become sonar waves that reflect from a target. The reflections from the target are received with a hydrophone on the ship.

Air based sonar projector array

Described herein is the use of large phase transformational strain in relaxor ferroelectric single crystals for broadband sound generation. The technique exploits the thermo-optical triggering and thus an opto-acoustic effect of ferroelectric phase transformation piezocrystals under mechanical bias conditions.

Thermo-optical method of phrase transformational transduction

A sensor system is provided comprising a Laser Doppler Vibrometer (LDV) that senses underwater sound via vibrations on an ice surface. In operation, a beam of the LDV measures a surface velocity and therefore an associated pressure signal from the ice surface due to an impinging underwater sound. The beam reflected from the surface carries the acoustic information back to the LDV. Using interferometry to derive the acoustic signal carried on the reflected beam; the LDV provides acoustic signal data in the form of a voltage signal. A computer processes the voltage signal as data that estimates a sound pressure level of the underwater source.

Laser-based method of detecting underwater sound through an ice layer

A device and system is provided for amplifying vibrations resulting from underwater acoustic signals. In operation, a laser interrogation beam is directed along an axis at the retro-reflector device and is responsive to reflections directed along the axis of the interrogation beam. The retro-reflector device reflects a signal back to a source and a tracking signal superimposed on an interrogation beam enables continuous sensing of the reflected signal to reduce signal dropout. A glint tracker is provided for tracking the tracking beam on the surface. A tracker system superimposes the tracking and interrogation beams and is responsive to reflected glints in order to establish a directional location. An interferometer responsive to the reflected interrogation beam produces an interference signal for enabling continuous measurement of surface vibrations.

Laser based acousto-optic sensing enhancement using tailored retro-reflectors

A method for locating defects in a target includes subjecting the target to an ultrasonic vibration. A first laser beam is then transmitted to the target and a reflection is received. A vibration signal is produced from the reflection that gives the target's response to the ultrasonic vibration. A digital image is produced of the target that includes the region of the first laser beam reflection. The digital images are overlaid with the vibration signal to provide overlaid data. The overlaid data is tested to determine a probability of the overlaid data being non-random. The probability is compared against a threshold to indicate a potential area of concern that may include defects.

Method of laser vibration defect analysis

A system for determining spatial coherence, temporal coherence or both of an optical signal includes a fiber bundle containing optical fibers. Optical fiber inputs are arranged in proximate groups having the same number of fibers. The groups can each receive a portion of the optical signal. Each fiber in the group has a gross length that differs from the other fibers, but each group has the same set of different gross lengths. The fibers are joined to a lens which spreads the optical signal and causes interference between portions of the signal. This interference is detected at a detector. A computer joined to the detector can measure spatial and temporal coherence from the interference. Other embodiments feature multiple detectors and reflection along the bundle.

Spatial and temporal coherence measurement system

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.

Remote blood pressure waveform sensing method

Remote blood pressure waveform sensing method and apparatus

A plurality of optical sensors are mounted to a housing made of optically conductive material. The housing seals the optical sensors from a water-filled tube which extends through said housing. The optically conductive material provides optical coupling with the water-filled cable tube whereby a plurality of light beams are directed through the housing and the water-filled tube in a predetermined pattern, which provides certainty of the absence or presence of a cable within the water-filled cable tube for a minimum cable diameter regardless of the orientation of the cable within the water-filled tube.

Outboard optical cable sensor system and method

An Unmanned Undersea Vehicle (UUV) docking system is provided in which the UUV is responsive to a first rotating light beam (which emits from a submarine) to begin a docking procedure. The UUV utilizes a photodetector to detect the first light beam and to guide the UUV toward the submarine by utilizing the first light beam. In one embodiment, the UUV reflects light from the first light beam back to the submarine. A photodetector on the submarine detects the reflected light to ascertain that the UUV is locked onto the first light beam. The submarine then stops rotating the light beam so that a trajectory of the UUV heads in the direction of a docking station which is positioned on the submarine.

Laser-based method for docking an unmanned underwater vehicle to a submarine

The present invention includes a system and method of use for communications from an in-air platform to a submerged platform. The system includes a laser positionable on the in-air platform above a water medium that sends a pulsed information-bearing laser beam containing a modulated communications signal to create and react in a non-linear regime manner with the water medium at an air/water interface. The beam vaporizes and optically breaks down a portion of the water medium, creates a shock wave and generates bubble oscillations at the vaporized portion. An acoustic sensor on the submerged platform detects these shock wave oscillations within the water medium and a demodulator-decoder that identifies these broadband acoustic transients that contain deterministically placed energy and demodulates-decodes the acoustic transients into the transmitted communications signals from the in-air platform.

Non-linear optoacoustic narrowband communications technique

A device and system to remotely detect vocalizations of speech. The skin located on the throat region of a speaking person or a reflective layer on the skin on the throat region vibrates in response to vocalizations of speech by the person. The vibrating skin or reflective layer is reflective of impinging radiation. A laser Doppler vibrometer transmits radiation onto the vibrating skin or the covering reflective layer and receives reflected radiation from the vibrating skin or reflective layer. The laser Doppler vibrometer generates voltage output signals that are representative of the speech causing the vibrations. A target tracker directs the impinging radiation and detects the reflected radiation to pass between the throat region and the laser Doppler vibrometer and includes a processor that removes non-speech signal artifacts from the voltage output signals. An interconnected audio speaker reproduces the speech from the voltage output signals.

Remote voice detection system

An acoustic sensor used in underwater applications. The sensor includes a reflective material adhered to a structure, such as an outer submarine hull or any marine vessel hull. A laser interferometer is placed on the side of the structure with the reflective material. The laser interferometer sends a plurality of laser beams, in sequence or all at one time, to a plurality of points across the retro-reflective material. The laser beams reflect back to the interferometer, which captures the reflected beams using receiving optics. The phase modulation of the reflected laser beams is compared to a reference laser beam within the interferometer to obtain the vibration velocity characteristics of the hull surface structure. Since the reflective material is adhered to the structure, the structure vibration is the same as the vibration of the reflective material. From this vibration, the acoustic pressure associated with the structure may be calculated.

Optical underwater acoustic sensor

A passive acoustic sensor that may be employed to detect sounds emanating from under the surface of a body of water. The sensor uses optics to determine vibration on the surface of a water body to detect sound pressure waves from underwater sound sources. The sensor is deployed above the surface and has no direct interaction with anything under the surface that may be emanating sounds. This allows the invention to operate without interfering with potential sound sources as well as allows for numerous deployment methods.

Passive optical detection of underwater sound

Optical fiber coupler for coupling fiber optic elements includes a first fiber optic element extending in a first direction to position a free end thereof in a selected zone, and a second fiber optic element extending into the selected zone from an opposite direction to position a free end of the second fiber optic element in the zone confronting the first fiber optic element free end. A cured optical grade epoxy resin body defines the zone and envelopes the free ends of the fiber optic elements, to effect physical and optical connection between the first and second fiber optic elements. Once cured, the housing material is removed leaving the completed coupler device. The free ends of the fiber optic elements are in close proximity, or in the case of coupling from one strand to a plurality of strands, in enough of a spaced relation, to permit required light diffusion.

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Cranston, RI, United States of America

Lynn T Antonelli