Litton Systems, Inc.

Northrop Grumman Guidance and Electronics Company, Inc.

Northrop Grumman Systems Corporation

Northrop Grumman Corpoation

Edward Kanegsberg

Henry C Abbink

Robert E Stewart

John G Mark

John P Rahn

Donald A Frederick

Thomas J Hutchings

Charles H Volk

Ralph A Patterson

Kenneth Marino

Bruce C Grover

Laurence G Cote

Sheridan W Hammons

John R Hall

Steven C Gillespie

Roger L Meyer

Daryl C Stjern, Deceased

Edmund W Rusche, Legal Representative

An aspect of the present invention relates to system and method for substantially obstructing magnetic flux. One aspect of the present invention provides an apparatus for substantially obstructing at least one magnetic flux path between an ambient space and a protected volume. The apparatus includes an inner shield, substantially enclosing the protected volume. The inner shield has at least one inner shield aperture extending therethrough to allow external access to the protected volume. An outer shield substantially encloses the inner shield. The outer shield has at least one outer shield aperture extending therethrough to allow internal access from the ambient space. The apparatus is configured to impede magnetic flux between at least one inner shield aperture and at least one outer shield aperture.

Systems and methods for obstructing magnetic flux while shielding a protected volume

An apparatus in one example comprises a polarization filter and a polarization analyzer. The polarization filter comprises a first polarization axis. The polarization analyzer comprises a second polarization axis. The polarization filter is configured to polarize detection light for a nuclear magnetic resonance (NMR) cell along the first polarization axis. The polarization analyzer is configured to receive the detection light from the NMR cell and pass a portion of the detection light to a processor for determination of angular rate information. The portion of the detection light passed to the processor is based on an orientation of the second polarization axis relative to the first polarization axis. The orientation is selected to maximize a signal-to-noise ratio of the detection light.

Polarization analyzer orientation with nuclear magnetic resonance gyroscope

The method and apparatus in one embodiment may have: a gyro housing containing a bias field; a bias field that generates a stable axial magnetic field; Xenon or other gas contained within at least a portion of the axial magnetic field, Xenon or other gas nuclear spins precessing at a constant angular rate with respect to the gyro housing in response to the axial magnetic field; wherein reversing a polarity of the bias field reverses a polarity of the magnetic field and a polarity of the precession of the Xenon or other gas nuclear spin, and wherein a reversing of the polarity of the gyro scalefactor thereby results without reversing a polarity of the gyro bias.

Self-calibrating nuclear magnetic resonance gyro

A cell in one example comprises an alkali metal and a coating of parylene on an interior surface of the cell. In one implementation, the alkali metal may be an optically pumped gaseous phase of an alkali metal. The parylene coating minimizes interaction of the excited state of the alkali metal, increases lifetime of the excited state, and minimizes interaction of nuclear spin states with the cell walls.

Micro-cell for NMR gyroscope

A method comprises the steps of providing a nuclear magnetic resonance cell with first, second, and third nuclear moment gases and at least one optically pumpable substance; obtaining first, second, and third measured precession frequencies that correspond to the first, second, and third nuclear moment gases, wherein the first, second, and third measured precession frequencies are altered from corresponding first, second, and third Larmor precession frequencies by a rotational rate and corresponding first, second, and third local magnetic fields; and determining the rotational rate with compensation for the first, second, and third local magnetic fields through employment of the first, second, and third measured precession frequencies.

Nuclear magnetic resonance gyroscope

An NMR gyroscope in one example comprises a support structure affixed within an enclosure, an NMR cell affixed to the support structure, a plurality of permanent magnets disposed about the NMR cell to produce a magnetic field within the cell, and a field coil disposed proximate the cell to produce a modulated magnetic field transverse to the magnetic field produced by the permanent magnets.

NMR gyroscope

A method for measuring intensity-type polarization non-reciprocity (PNR) bias error in an interferometric fiber optic gyroscope (IFOG) using birefringence modulation. The counter-propagating waves in the fiber optic loop of the IFOG are modulated with a slowly varying voltage signal, such as a triangle wave, ramp or sine wave signal, to cause birefringence modulation. A peak-to-peak amplitude of a resultant output signal is measured to determine the intensity-type PNR bias error of the IFOG.

Method for measurement of PNR bias error in an interferometric fiber

The intensity and frequency variation due to retroscatter in a ring laser gyroscope are determined and used to correct the gyro scale factor. The orthogonal types of scatter due to dielectric variation and due to height variation, which lead to common mode phase delays of 0 and .pi./2 respectively are taken into account in calculating the correction to the scale factor. The scale factor errors are determined in terms of observable quantities. Scale factor error control is accomplished by extracting a portion of both of the two counterpropagating light beams and measuring their respective intensities, creating intensity modulation indices representative of the sum and difference intensities, using closed loop control of the real-time difference between the intensities of the beam in the ring laser gyro to reduce scale factor variation using push-pull mirror control of at least two mirrors. The residual error after push-pull mirror control minimization is output for use by a navigation system computer.

Ring laser gyroscope scale factor error control apparatus and method

Phase errors that occur when a dithered ring laser gyroscope enters its deadband are measured, and a correction is applied to the output of the ring laser gyroscope to compensate for these phase errors. The counterpropagating beams in a ring laser gyroscope are heterodyned to produce a pair of quadrature heterodyne signals that indicate the angular output of the laser ring laser gyroscope. The phase angle error between one of the heterodyne signals and either the sum or difference of the separate beam intensities is determined, The phase angle error signal is used to produce a control signal for adjusting the output of the ring laser gyroscope to correct for errors introduced at or near turnarounds in the dither cycle.

Apparatus and method for correcting ring laser gyroscope phase angle

Disclosed herein is a ring laser gyroscope having a non-reciprocal polarization rotation device such as a Faraday rotator configured to provide, through use of a Faraday magnet, a relatively uniform magnetic field across the profile of the Faraday rotator. By providing a uniform magnetic field across the diameter of the Faraday rotator, the magnetic lensing effects are reduced and the thermal sensitivity of the gyroscope's bias is substantially reduced.

Faraday magnet for the reduction of multi-oscillator bias thermal

A nuclear magnetic resonance gyroscope is disclosed that operates on the principle of sensing angular rotation rate as a shift in the Larmor frequency of one or more nuclear species that possess nuclear magnetic moments.

Growing community of inventors

Pacific Palisades, CA, United States of America

Edward Kanegsberg