Litton Systems, Inc.

Northrop Grumman Systems Corporation

Patrick J Welton

Eric Lee Goldner

A Douglas Meyer

James Kengo Andersen

Akbar Arab-Sadeghabadi

Michael J Tweedy

Bruce A Danver

Dennis P Bevan

Gregory M Nau

John Cappi

Liana Dang

A fiber optic acoustic sensor that detects pressure waves from all incident angles features multiple mandrels orthogonally disposed to provide omni-directional sensing capability. The topology of the mandrels prevents frequency response drop-off characteristic of cylindrical sensors at wavelengths smaller than &#xbd; the length of the acoustic cylinder. The larger operating bandwidth and omni-directional sensing capability makes this fiber optic acoustic sensor a suitable choice for a wide range of applications.

Tri axis high frequency fiber optic acoustic sensor

A pair of fiber optic coils are mounted on opposite sides of a flexural disk and are arranged to form an interferometer that produces an output signal in response to acceleration of the flexural disk. The flexural disk is mounted in a housing having first and second end plates with a sidewall extending between them. A support member extends between the end plates and through a central passage in the flexural disk. A pair of compressive dampers is mounted in the housing between the flexural disk and the housing end plates. A shear damper mounted on the central support member exerts a radial force on an inner edge of the central passage in flexural disk to dampen vibrations of the flexural member and control the output signal amplitude over a selected frequency range.

High performance fiber optic accelerometer

An acoustic array including a plurality of acoustic sensors positioned at predetermined telemetry points for measuring the acoustic energy from the surrounding environment. The acoustic sensors are each positioned within a fluid-filled pocket in the acoustic array, wherein each the various fluid-filled pockets are separated from each other by a section of solid fill buoyant material. The sections of solid fill material control the buoyancy of the acoustic array. The acoustic array is surrounded by a longitudinally extending outer hosewall which encloses the acoustic array and forms the fluid-filled pockets between the sections of solid fill material. A strength member is extended longitudinally throughout the length of the acoustic array to provide a load bearing mechanism for distributing longitudinal tensile loads applied to the acoustic array, while support spacers are situated within the acoustic array to provide radial support for the acoustic array. The acoustic array is formed of a lightweight and electrically passive structure which allows water to be used as the fill fluid for the pockets. Using water as the fill fluid provides an environmentally-safe fill fluid having buoyancy characteristics which are not significantly altered by its mixture with water from the surrounding environment should a rupture in the hosewall occur.

Solid fill acoustic array

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Thousand Oaks, CA, United States of America

Patrick J Welton