公开(公告)号：NO20013609A

公开(公告)日：2002-04-26

申请号：NO20013609

申请日：2001-07-20

Applicant: LITTON SYSTEMS INC

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

IPC: G01H20060101 ,  G01H9/00 ,  H04R1/46

公开(公告)号：NO20005442D0

公开(公告)日：2000-10-27

申请号：NO20005442

申请日：2000-10-27

Applicant: LITTON SYSTEMS INC

Inventor： FREDERICK DONALD A ,  CARTER MICHAEL J ,  FERSHT SAMUEL N ,  WINSLOW DAVID C

IPC: G01H9/00 ,  G01V1/18 ,  G01V1/40 ,  G01V

Abstract: A system for sensing subterranean acoustic waves emitted from an acoustic source includes a plurality of laser sources (LS1-LS6), a plurality of subterranean optical sensors (1000), at least one optical detector (D1-D16), and electronics (601). The laser sources each emit light at a different frequency. The subterranean optical sensors are hydrophones (1000) that receive the light and alter the light in response to the acoustic waves. The optical detector (D1-D16) receives the altered light and outputs an electrical signal. The electronics (601) receives the electrical signal and converts it into seismic data format. The hydrophones (1000) are able to operate at pressures of at least 5,000 psi and temperatures of at least 130 degrees Celsius. The hydrophone (1000) may be housed in a cable (1002) having a diameter of less than about 1.5 inches. The hydrophone's sensor preferably includes a reference mandrel (1110), two sensing mandrels (1120), and a telemetry can (1104), all of which are aligned in a coaxial, end-to-end configuration to reduce the profile of the hydrophone (1000). Flexible interlinks (1296) having grooves therein for receiving optical fiber join the mandrels (1110, 1120) together. The reference mandrel (1110) and sensing mandrels (1120) advantageously have hemispherically-shaped endcaps (1264), permitting them to operate at high pressure.

公开(公告)号：CA2243348A1

公开(公告)日：1999-01-30

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 element about a sensing axis perpendicular to the drive axis for input rotation rates 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 sensing axis.

公开(公告)号：IT1182156B

公开(公告)日：1987-09-30

申请号：IT4761285

申请日：1985-01-29

Applicant: LITTON SYSTEMS INC

Inventor： FERSHT RENA S ,  FERSHT SAMUEL N

IPC: G01P9/00 ,  G01C19/64 ,  G01C19/66 ,  G01C19/70 ,  H01S3/083 ,  G01P

公开(公告)号：NO860782A

公开(公告)日：1986-03-03

申请号：NO860782

申请日：1986-03-03

Applicant: LITTON SYSTEMS INC

Inventor： FERSHT SAMUEL N ,  FERSHT RENA S

IPC: G01C19/64 ,  G01C19/70 ,  G01P9/00 ,  H01S3/083 ,  G01C

CPC classification number: G01C19/70

公开(公告)号：GB2153585A

公开(公告)日：1985-08-21

申请号：GB8500719

申请日：1985-01-11

Applicant: LITTON SYSTEMS INC

Inventor： FERSHT RENA S ,  FERSHT SAMUEL N

IPC: G01P9/00 ,  G01C19/64 ,  G01C19/66 ,  G01C19/70 ,  H01S3/083

Abstract: Three sets of laser angular sensors (11,12,13) corresponding to three angularly disposed sensing planes are mounted on a common instrument block (10) and each provided with mechanical dithering devices for inducing an oscillatory mechanical motion to prevent or retard lock-in. A compensating mass (20) is mounted on the same instrument block and includes a selectively controllable mechanical dithering device. Dithering the compensating mass at an appropriately selected amplitude and frequency automatically compensates for dither interaction (coning) between the three sensors (11,12,13).

公开(公告)号：FR2558951A1

公开(公告)日：1985-08-02

申请号：FR8418722

申请日：1984-12-07

Applicant: LITTON SYSTEMS INC

Inventor： FERSHT RENA S ,  FERSHT SAMUEL N

IPC: G01P9/00 ,  G01C19/64 ,  G01C19/66 ,  G01C19/70 ,  H01S3/083 ,  G05D19/00

公开(公告)号：CA2415445C

公开(公告)日：2006-07-18

申请号：CA2415445

申请日：2001-07-25

Applicant: LITTON SYSTEMS INC

Inventor： FERSHT SAMUEL N

IPC: G01P15/03 ,  G01P15/00 ,  G01P15/093

Abstract: A fiber optic particle motion accelerometer has a housing with a mid-section mounted therein such that the mid-section flexes in response to acceleration along a sensing axis. A proof mass is mounted to an outer edge of the mid- section. A first spiral-wound optical fiber coil is mounted to a first side of the mid-section and a second spiral-wound optical fiber coil is mounted to a second side of the mid-section. A first hinge is formed in the mid-section adjacent the mounting of the mid-section in the housing, and a second hinge is formed in the mid-section between the proof mass and the first and second fiber optic coils. The optical fiber coils are included in an outerferometer such that acceleration along the sensing axis produces a phase difference between optical signals propagating in the optical fiber coils.

公开(公告)号：DE60111137T2

公开(公告)日：2006-05-04

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 ,  A61K31/164 ,  G01P15/093 ,  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).

公开(公告)号：CA2240727C

公开(公告)日：2005-11-08

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 fe d into the entry point (25) of each two-path 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.