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    14.
    发明专利
    未知

    公开(公告)号：NO982586D0

    公开(公告)日：1998-06-05

    申请号：NO982586

    申请日：1998-06-05

    Applicant: LITTON SYSTEMS INC

    Inventor： HALL DAVID B ,  FERSHT SAMUEL N

    IPC: G01P15/03 ,  G01B9/02 ,  G01B11/00 ,  G01H9/00 ,  G01L9/00 ,  G02F

    Abstract: A system (10) for measuring changes in an environmental parameter, such as velocity or pressure, includes an optical signal source (11, 12, 13) for providing a pulsed, coherent light signal, and an interferometer having first and second optical legs (33, 35) of unequal optical path lengths. The signal is split into first and second beams that are respectively directed into the first and second optical legs of the interferometer. A fixed mirror (41) reflects the first beam received at the end of the first optical leg (33) . An optical pick-off (51) includes a movable mirror, positioned to reflect the second beam received from the end of the second optical leg (35). The movable mirror is movable in response to changes in the value of the parameter to be measured. An optical coupler (38) combines the first and second beams after they have been reflected back into their respective optical legs, producing an interference signal, which is detected by an optical detector (39). The detector (39) generates an electronic signal having a value indicative of the value of the interference signal. The electronic signal is analyzed to correlate its value to changes in the value of the environmental parameter to be measured.

    SENSING METHOD AND APPARATUS
    15.
    发明专利
    SENSING METHOD AND APPARATUS 未知

    公开(公告)号：CA2240727A1

    公开(公告)日：1998-05-22

    申请号：CA2240727

    申请日：1997-11-14

    Applicant: LITTON SYSTEMS INC

    Inventor： FERSHT SAMUEL N ,  FREDERICK DONALD A

    IPC: G01L1/24 ,  G01B9/02 ,  G01D5/353 ,  G01J9/02 ,  G01K11/12

    Abstract: The invention is a method and apparatus for determining the phase difference of light waves (31) after propagating through each of one or more two-path pairs, a two-path pair being two optical transmission paths connecting a common entry point (25) to a common exit point (29). Coherent light pulses (27) of predetermined duration are fed into the entry point (25) of each twopath pair in a group of two-path pairs at predetermined time intervals, the pulse duration being subdivided into a plurality of predetermined time segments. The phase difference for each two-path pair is determined from amplitude values of the electrical signal.

    16.
    发明专利
    未知

    公开(公告)号：DE60035118D1

    公开(公告)日：2007-07-19

    申请号：DE60035118

    申请日：2000-10-26

    Applicant: LITTON SYSTEMS INC

    Inventor： FERSHT SAMUEL N ,  HALL DAVID B ,  BATHELT CARL

    IPC: G01H9/00 ,  G01H1/00 ,  G01P15/08 ,  G01P15/093 ,  G01V1/18 ,  G02B6/00

    Abstract: A fiber optic seismic sensor includes a central support assembly formed of a metal such as aluminum. A support plate has an inner portion retained within the central support assembly and an outer portion that extends beyond the central support assembly. A pair of hollow cylindrical substrates are mounted in axial alignment on opposite sides of the outer portion of the support plate with the central support assembly extending through the centers of the substrates. The central support assembly comprises a first central support member having a cavity in one end, and a second central support member having a projection extending therefrom and arranged to be received within the cavity in the first central support member. The support plate includes a passage arranged to receive the projection such that the inner portion of the support plate is retained between the first and second central support members. A first spiral-wound optical fiber coil is formed on an outer end of the first substrate, and a second spiral-wound optical fiber coil is formed on an outer end of the second substrate. An interferometer includes the first spiral-wound optical fiber coil in a first leg and the second spiral-wound optical fiber coil in a second leg. Acceleration along an axis perpendicular to the planes of the optical fiber coils causes a deflection in the support plate, which changes the pathlength difference between the legs of the interferometer.

    17.
    发明专利
    未知

    公开(公告)号：DE60111137D1

    公开(公告)日：2005-07-07

    申请号：DE60111137

    申请日：2001-07-19

    Applicant: LITTON SYSTEMS INC

    Inventor： GOLDNER ERIC LEE ,  TWEEDY MICHAEL J ,  FERSHT SAMUEL N ,  HALL DAVID B

    IPC: G01H9/00 ,  G01P15/093 ,  A61K31/164 ,  G01V1/18

    Abstract: A displacement sensor (21) and an acceleration sensor (23) are mounted to a common support member. The displacement sensor (21) comprises a first circular flexural disk (40) having a natural frequency less than the frequency range of the acoustic waves of interest. Spiral-wound optical fiber coils (53, 55) are mounted to opposite sides of the first flexural disk (40). The acceleration sensor (23) comprises a second flexural disk (68) having a natural frequency greater than the frequency range of the acoustic waves. Spiral-wound optical fiber coils (53, 55) are mounted to opposite sides of the second flexural disk (68). A fiber optic interferometer provides an output signal that is a combination of signals output from the displacement sensor (21) and the acceleration sensor (23). The displacement sensor (21) includes an inertia ring (58) mounted to an edge of the first flexural disk (40) to keep it nearly stationary when an acoustic wave in the selected frequency range is incident upon the housing (22). The flexural disks (40, 68) include upper and lower rings (72, 74) spaced apart from the support post with portions of the disks (40, 68) between the rings (72, 74) and the support post defining hinges (75) at which the flexural disks (40, 68) flex in response to acceleration of the support member along its longitudinal axis. The surfaces of the first and second flexural disks (40, 68) preferably include grooves (84) extending between the upper rings (72) and the outer edges of the flexural disks (268, 274). The grooves (84) are arranged to allow lengths of optical fiber adjacent the rings (72, 74) to pass under the optical fiber coils (77, 79) that are formed on the surfaces of the flexural disks (40, 68).

    OPTICAL WAVEGUIDE SENSOR SYSTEM FOR REMOTE DETECTION
    18.
    发明专利
    OPTICAL WAVEGUIDE SENSOR SYSTEM FOR REMOTE DETECTION 未知

    公开(公告)号：CA2278356C

    公开(公告)日：2005-03-22

    申请号：CA2278356

    申请日：1999-07-22

    Applicant: LITTON SYSTEMS INC

    Inventor： FERSHT SAMUEL N ,  HALL DAVID B ,  FREDERICK DONALD A

    IPC: G01B9/02 ,  G01H9/00 ,  G01V1/16 ,  G01V1/22

    Abstract: An optical waveguide (28) formed in an integrated optics substrate (30) is included in an optical path of an interferometer (51). An optical signal source (12) is arranged to provide an optical signal to the interferometer (51). A channel waveguide phase modulator (38) its formed on the substrate (30) and arranged to phase modulate optical signals guided by the optical waveguide (28). Signals from a geophon e (50) arranged to produce an electrical signal in response to mechanical vibration s are input to the phase modulator (38). The geophone (50) is connected to the channel waveguide phase modulator ((38) such that the electrical signal modulates the phase of the optical signal guided by the optical waveguide (28) so that the interference pattern output from the interferometer (51) indicates the amplitude of the mechanical vibrations . One or more optical fibers (24) are included in the interferometer (51) and are arranged to provide a mismatch between the interferometer path lengths

    TWO AXIS NAVIGATION GRADE MICROMACHINED ROTATION SENSOR SYSTEM
    19.
    发明专利
    TWO AXIS NAVIGATION GRADE MICROMACHINED ROTATION SENSOR SYSTEM 未知

    公开(公告)号：CA2243348C

    公开(公告)日：2002-08-27

    申请号：CA2243348

    申请日：1998-07-15

    Applicant: LITTON SYSTEMS INC

    Inventor： WYSE STANLEY F ,  FERSHT SAMUEL N ,  STEWART ROBERT E

    IPC: G01C19/56 ,  G01C19/58 ,  G01P3/00

    Abstract: A mounting plate is placed in a housing with a plurality of compliant, damped pads arranged between the housing and the mounting plate. A hub arranged to produce rotational oscillations about a drive axis extends from the mounting plate, and a first drive member is connected to the hub. A first sensing apparatus having a support element is connected to the drive member to transmit rotational oscillations of the drive member about the drive axis to the support element. The first sensing apparatus includes a sensing element connected to the support element and arranged to oscillate with the support element about the drive axis. The sensing element is arranged to oscillate rotationally relative to the support elemen t about a sensing axis perpendicular to the drive axis for input rotation rate s of the frame about an input axis which is perpendicular to both the sensing axis and the drive axis. A second drive member is connected to the first drive member and is arranged to produce rotational oscillations about the drive axis that are opposite in direction to the rotational oscillations produced by the first drive member. The second sensing apparatus has a second sensing element arranged to oscillate rotationally relative to the support element about second sensing axis that is parallel to the first sensingaxis.

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