Ralph K Patterson

US Patent:

7280218, Oct 9, 2007

Filed:

Jan 6, 2005

Appl. No.:

11/030248

Inventors:

Robert A. Mitchell - Woodland Hills CA, US
Christine E. Geosling - Calabasas CA, US
Ralph A. Patterson - Moorpark CA, US

Assignee:

Litton Systems Inc. - Woodland Hills CA

International Classification:

G01C 19/66

US Classification:

356459, 372 94

Abstract:

An apparatus and method is provided for facilitating ionization of a gas medium of a laser gyroscope. The apparatus and method employ a solid state light emitting device as a start aid for the laser gyroscope. The solid state light emitting device has a wavelength at or below a threshold wavelength based on a work function of a cathode coating material to prompt ionization of a gas medium within the laser gyroscope.

US Patent:

58568670, Jan 5, 1999

Filed:

Jul 28, 1997

Appl. No.:

8/901504

Inventors:

John P. Rahn - West Hills CA
Ralph A. Patterson - MoorPark CA

Assignee:

Litton Systems, Inc. - Woodland Hills CA

International Classification:

G01N 2100

US Classification:

356 731

Abstract:

The invention is a method and apparatus for quantitatively characterizing the pressure-induced nonreciprocity of a fiber-optic coil where the pressure-induced nonreciprocity is a property of a fiber-optic coil which pertains to the degree to which light beams, initially in phase, differ in phase as a result of traversing the fiber-optic coil in reverse directions while the fiber-optic coil is being subjected to a time-varying pressure. The method comprises the steps of applying time-varying pressure to the fiber-optic coil for a predetermined time period, measuring the phase difference of light beams traversing the fiber-optic coil in reverse directions during the predetermined time period, and obtaining a measure of the nonreciprocity of the fiber-optic coil utilizing the measured phase difference. If the time-varying pressure is specified by a first function of time, the measure of the nonreciprocity is the integral over the predetermined time period of the product of a second function of time and either (1) the phase difference of light beams traversing the fiber-optic coil in reverse directions during the predetermined time period or (2) the integral over time of the phase difference. The second function is chosen such that the measure of the nonrecipocity has a signal-to-noise ratio of at least one.

US Patent:

57423903, Apr 21, 1998

Filed:

Nov 19, 1996

Appl. No.:

8/751984

Inventors:

Amado Cordova - West Hills CA
Robert J. Hoover - Newbury Park CA
Thomas McLean - Woodland Hills CA
Ralph A. Patterson - Moorpark CA
John P. Rahn - West Hills CA

Assignee:

Litton Systems, Inc. - Woodland Hills CA

International Classification:

G01C 1964

US Classification:

356350

Abstract:

A potted sensor coil for a fiber optic gyroscope includes an inter-layer stress relief layer of lubricating material. The coil is wound into a known pattern. Various coil configurations can be realized in which a coating layer of lubricant relieves stressing at the interface between the outer jacket of the fiber and the coil potting material.

US Patent:

60409088, Mar 21, 2000

Filed:

Jul 28, 1998

Appl. No.:

9/123626

Inventors:

John P. Rahn - West Hills CA
Ralph A. Patterson - Moorpark CA
Amado Cordova - Woodland Hills CA

Assignee:

Litton Systems, Inc. - Woodland Hills CA

International Classification:

G01C 1972

US Classification:

356350

Abstract:

A method and apparatus for reducing the temperature-dependent Shupe bias of a potted gyro sensor coil pack to near-zero is provided by selectively adjusting the manner in which CCW and CW fiber leads are attached to the coil pack or the coil mount. The invention recognizes the inevitable existence of a strain differential between the CW and CCW-wound portions of a symmetrically-wound fiber coil. Leads affixed to the ends of the CW and CCW-wound halves of the coil are selectively bonded in accordance with principles for creating a counteracting temperature-dependent stress differential whereby temperature-dependent Shupe bias is substantially eliminated from the gyro output.

US Patent:

57612250, Jun 2, 1998

Filed:

May 23, 1996

Appl. No.:

8/652770

Inventors:

Bernard C. Fidric - Woodland Hills CA
Ronald James Michal - Wrightwood CA
James Ross Steele - Northridge CA
Eric Lee Goldner - Valencia CA
Ralph A. Patterson - Moorpark CA

Assignee:

Litton Systems, Inc. - Woodland Hills CA

International Classification:

H01S 330

US Classification:

372 6

Abstract:

A power boosted source of broadband optical power comprising a broadband light source, optical fiber amplifier and a relative intensity noise reduction system. The optical fiber amplifier amplifies the power level of the optical input signal to provide a power boosted source of broadband optical power out of an output port. A coupler samples a portion of the broadband optical power out of the output port as a sample portion signal. A detector and transimpedance amplifier detect the optical signal and provide a buffered signal having an instantaneous amplitude that faithfully characterizes the intensity of the sample portion signal. A bandpass amplifier amplifies the buffered signal and provides an output control signal to a light source responsive to a composite bias and control current for providing an output optical signal. The output optical signal is coupled to the input of the optical fiber amplifier to be the optical input signal to the optical fiber amplifier. The output optical signal from the ELED has a substantially constant output intensity level and smooth and bell shaped broad band spectrum with a center optical wavelength within the gain bandwidth of the optical fiber amplifier.

US Patent:

53332148, Jul 26, 1994

Filed:

Feb 12, 1993

Appl. No.:

8/017678

Inventors:

Sidney X. Huang - West Hills CA
Ronald J. Michal - Wrightwood CA
Ralph A. Patterson - Moorpark CA
George A. Pavlath - Thousand Oaks CA

Assignee:

Litton Systems, Inc. - Beverly Hills CA

International Classification:

G01B 902

US Classification:

385 12

Abstract:

Apparatus for suppressing the bias errors induced by the Faraday effect in the output of a sensor coil exposed to a magnetic field. Arrangements are formed at two leads of the sensor coil for compensating the bias shifts. One of such arrangements comprises at least one loop of optical fiber for compensating the effect induced by the magnetic field component oriented transverse to the axis of the sensor coil while the other comprises at least one loop oriented at a predetermined pitch angle for compensating the effect induced by a magnetic field component along the axis. In each case, a predetermined degree of twist of a preselected fiber twist mode is imposed upon the compensator loop for creating a counteracting, corrective Faraday effect. Cross-coupling does not occur between the two compensators as their twist rate perodicities are unequal.