公开(公告)号：DE69921768D1

公开(公告)日：2004-12-16

申请号：DE69921768

申请日：1999-07-20

Applicant: LITTON SYSTEMS INC

Inventor： TAZARTES A ,  MARK G

IPC: G01C19/72

Abstract: A method and apparatus are provided for initializing a closed-loop fiber optic gyroscope system of the type that includes a fiber optic gyroscope for generating an interferometric measurement of phase shift and a demodulator for converting the gyroscope output to a corresponding value in a predetermined format for application to a feedback integrator. In contrast to prior art methods and apparatus that require recapture, the present invention relies upon the concept of resetting the initial value received from the gyro to a corresponding value that lies within the zeroeth fringe of a gyro output. The feedback integrator includes an arithmetic unit with feedback. The resetting process consists of the performance of an operation upon the value. Such operations include shifting and copying functions when the predetermined format is two's-complement logic, integer function when the predetermined format is fixed point logic and both INTEGER and ROUND functions when the predetermined format is floating point logic.

公开(公告)号：DE69921768T2

公开(公告)日：2005-10-27

申请号：DE69921768

申请日：1999-07-20

Applicant: LITTON SYSTEMS INC

Inventor： TAZARTES A ,  MARK G

IPC: G01C19/72

Abstract: A method and apparatus are provided for initializing a closed-loop fiber optic gyroscope system of the type that includes a fiber optic gyroscope for generating an interferometric measurement of phase shift and a demodulator for converting the gyroscope output to a corresponding value in a predetermined format for application to a feedback integrator. In contrast to prior art methods and apparatus that require recapture, the present invention relies upon the concept of resetting the initial value received from the gyro to a corresponding value that lies within the zeroeth fringe of a gyro output. The feedback integrator includes an arithmetic unit with feedback. The resetting process consists of the performance of an operation upon the value. Such operations include shifting and copying functions when the predetermined format is two's-complement logic, integer function when the predetermined format is fixed point logic and both INTEGER and ROUND functions when the predetermined format is floating point logic.

公开(公告)号：DE69921768T9

公开(公告)日：2006-04-27

申请号：DE69921768

申请日：1999-07-20

Applicant: LITTON SYSTEMS INC

Inventor： TAZARTES A ,  MARK G

IPC: G01C19/72

Abstract: A method and apparatus are provided for initializing a closed-loop fiber optic gyroscope system of the type that includes a fiber optic gyroscope for generating an interferometric measurement of phase shift and a demodulator for converting the gyroscope output to a corresponding value in a predetermined format for application to a feedback integrator. In contrast to prior art methods and apparatus that require recapture, the present invention relies upon the concept of resetting the initial value received from the gyro to a corresponding value that lies within the zeroeth fringe of a gyro output. The feedback integrator includes an arithmetic unit with feedback. The resetting process consists of the performance of an operation upon the value. Such operations include shifting and copying functions when the predetermined format is two's-complement logic, integer function when the predetermined format is fixed point logic and both INTEGER and ROUND functions when the predetermined format is floating point logic.

公开(公告)号：DE69725275T2

公开(公告)日：2004-08-12

申请号：DE69725275

申请日：1997-06-26

Applicant: LITTON SYSTEMS INC

Inventor： MARK G ,  TAZARTES A ,  CORDOVA AMADO ,  CHERBETTCHIAN H ,  GOLDNER L

IPC: G01C19/72

Abstract: A gyroscope assembly (10) includes a ring-shaped fiber optic coil (14) and a coil conforming enclosure (12, 16) of high magnetic permeability ferromagnetic material. The enclosure is ring-shaped to conform with the shape of the coil, and includes a portion (22) extending within the internal hole of the coil ring. Therefore, the coil is intimately and fully encased within high magnetic permeability material. In particular, the enclosure comprises a coil supporting spool (12) and a cover (16) secured to the spool. The spool includes a base (18) which is provided with a central hole (20) and a tubular wall (22) extending perpendicularly from the base. Coil (14) is bonded to base (18). Both the spool and the cover are formed of high magnetic permeability material, and the cover is placed about the fiber optic coil and attached to the spool. The coefficient of thermal expansion material used for the spool is matched to that of the coil pack to minimize stress imposed upon the fiber. An outer shield (28), roughly cylindrical in shape, may be further attached to the outside of the inner, toroidal shield, and the two shields are separated by a layer of low magnetic permeability material, such as of low magnetic permeability stainless steel or aluminum.

公开(公告)号：DE69725275D1

公开(公告)日：2003-11-06

申请号：DE69725275

申请日：1997-06-26

Applicant: LITTON SYSTEMS INC

Inventor： MARK G ,  TAZARTES A ,  CORDOVA AMADO ,  CHERBETTCHIAN H ,  GOLDNER L

IPC: G01C19/72

Abstract: A gyroscope assembly (10) includes a ring-shaped fiber optic coil (14) and a coil conforming enclosure (12, 16) of high magnetic permeability ferromagnetic material. The enclosure is ring-shaped to conform with the shape of the coil, and includes a portion (22) extending within the internal hole of the coil ring. Therefore, the coil is intimately and fully encased within high magnetic permeability material. In particular, the enclosure comprises a coil supporting spool (12) and a cover (16) secured to the spool. The spool includes a base (18) which is provided with a central hole (20) and a tubular wall (22) extending perpendicularly from the base. Coil (14) is bonded to base (18). Both the spool and the cover are formed of high magnetic permeability material, and the cover is placed about the fiber optic coil and attached to the spool. The coefficient of thermal expansion material used for the spool is matched to that of the coil pack to minimize stress imposed upon the fiber. An outer shield (28), roughly cylindrical in shape, may be further attached to the outside of the inner, toroidal shield, and the two shields are separated by a layer of low magnetic permeability material, such as of low magnetic permeability stainless steel or aluminum.

公开(公告)号：DE69516498T2

公开(公告)日：2000-11-30

申请号：DE69516498

申请日：1995-07-24

Applicant: LITTON SYSTEMS INC

Inventor： TAZARTES A ,  HIGBEE A ,  FLAMM K ,  MARK G

IPC: G01J1/44 ,  H03F3/08 ,  G01C19/72 ,  H03F1/08

Abstract: An amplifier topology for receiving signals output from a fiber optic rotation sensor and producing voltages that may be processed to determine the rotation rate includes a photodiode for receiving an optical signal and producing a corresponding electrical photodiode output signal. An ultra low noise and ultra low capacitance differential input stage is connected to receive the photodiode output signal. An operational amplifier having low noise and ultra-wide bandwidth is connected to the ultra low capacitance differential input stage to receive the output signal therefrom as a driving signal and to produce a low noise output signal. The differential input stage comprises a first amplifier circuit that includes a first transistor connected to the photodetector to act as a first buffer having low noise, low capacitance and unity gain. The first amplifier circuit also includes a second transistor configured as a first voltage follower connected between the output of the first buffer and the operational amplifier to isolate the output of the first buffer from parasitic capacitive loading from a biasing network. The differential input stage further comprises a second a second amplifier circuit that includes a third transistor having an input connected to a reference potential, the third transistor acting as a second buffer having low noise, low capacitance and unity gain. The second amplifier circuit also includes a fourth transistor configured as a second voltage follower connected between the output of the second buffer and the operational amplifier.

公开(公告)号：DE69516498D1

公开(公告)日：2000-05-31

申请号：DE69516498

申请日：1995-07-24

Applicant: LITTON SYSTEMS INC

Inventor： TAZARTES A ,  HIGBEE A ,  FLAMM K ,  MARK G

IPC: G01J1/44 ,  H03F3/08 ,  G01C19/72 ,  H03F1/08

Abstract: An amplifier topology for receiving signals output from a fiber optic rotation sensor and producing voltages that may be processed to determine the rotation rate includes a photodiode for receiving an optical signal and producing a corresponding electrical photodiode output signal. An ultra low noise and ultra low capacitance differential input stage is connected to receive the photodiode output signal. An operational amplifier having low noise and ultra-wide bandwidth is connected to the ultra low capacitance differential input stage to receive the output signal therefrom as a driving signal and to produce a low noise output signal. The differential input stage comprises a first amplifier circuit that includes a first transistor connected to the photodetector to act as a first buffer having low noise, low capacitance and unity gain. The first amplifier circuit also includes a second transistor configured as a first voltage follower connected between the output of the first buffer and the operational amplifier to isolate the output of the first buffer from parasitic capacitive loading from a biasing network. The differential input stage further comprises a second a second amplifier circuit that includes a third transistor having an input connected to a reference potential, the third transistor acting as a second buffer having low noise, low capacitance and unity gain. The second amplifier circuit also includes a fourth transistor configured as a second voltage follower connected between the output of the second buffer and the operational amplifier.