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公开(公告)号：CA2232630A1
公开(公告)日：1998-02-05
申请号：CA2232630
申请日：1997-06-26
Applicant: LITTON SYSTEMS INC
Inventor： CORDOVA AMADO , GOLDNER ERIC L , MARK JOHN G , CHERBETTCHIAN AGOP H , TAZARTES DANIEL A
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.
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公开(公告)号：CA2175636A1
公开(公告)日：1997-03-01
申请号：CA2175636
申请日：1996-05-02
Applicant: LITTON SYSTEMS INC
Inventor： MARK JOHN G , TAZARTES DANIEL A , TAZARTES DAVID I
IPC: G01C19/72
Abstract: A loop controller for a fiber optic gyroscope employs distributed data processing to compress numerous additional useful functions into each loop transit time. The architecture of the loop controller includes a field programmable gate array for generating variables of varying sign. In addition, the array acts to buffer the transmission of parameters between the gyro processor and an auxiliary processor. The auxiliary processor updates such parameters (which do not require updating every loop transit time) and a number of such parameters are multiplied by values generated by the array in operations performed by the gyro processor that replace what would otherwise require throughput intensive test and branch operations. The combination of the offloading of selected variable and parameter generation and updating with programming of the gyro processor for parallel processing permits the loop controller to perform numerous useful operations not previously possible during a realistic loop transit time.
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公开(公告)号：IT1267106B1
公开(公告)日：1997-01-24
申请号：ITRM920010
申请日：1992-01-09
Applicant: LITTON SYSTEMS INC
Inventor： MARK JOHN G , TAZARTES DANIEL A
IPC: G01C19/66
Abstract: A ring laser gyro having a ring laser that preferably has four legs and four corner mirrors. At least one of the corner mirror is partly transmissive, and the transmitted beam is sensed and converted into a digital signal. The digital signal is fed back in two computer loops to at least one digital-to-analog converter, and thence to a transducer which drives at least one corner mirror inward and outward. One of the computer loops includes a stepped demodulator having four steps per cycle. The steps have voltages at the operating voltage of the transducer, that voltage plus an increment, the operating voltage, and that voltage less a decrement. The first loop sends an operating voltage to the digital-to-analog converters. The second loop demodulates the beam signal at a second harmonic of the demodulation of the first loop to produce a voltage signal which controls the amplitude of dithering of the movable mirrors. A stepped modulator, in synchronism with the demodulator of the first loop, delivers a modulation signal to the digital-to-analog converters to step the movable mirrors. The operating voltage moves the mirrors into a position wherein the laser cavity operates at its intensity mode peaks.
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公开(公告)号：CA2172524A1
公开(公告)日：1996-02-08
申请号：CA2172524
申请日：1995-07-24
Applicant: LITTON SYSTEMS INC
Inventor： TAZARTES DANIEL A , HIGBEE JOHN H , TAZARTES JACQUES A , FLAMM JUERGEN K P , MARK JOHN G
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 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.
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公开(公告)号：CA2063165A1
公开(公告)日：1995-11-18
申请号：CA2063165
申请日：1992-03-17
Applicant: LITTON SYSTEMS INC
Inventor： MARK JOHN G , TAZARTES DANIEL A , EBNER ROBERT E , DAHLEN NEAL J , DATTA NIBIR K
Abstract: Disclosed herein is a Ring Laser Gyroscope Enhanced Resolution System comprising, in a preferred embodiment, a sampling frequency modulation phase-locked loop (or "chirp") which is used in combination with the fast filter. Enhanced resolution is achieved by using the fast filter (preferably a moving average digital filter) to gather optically integrated rate data and accumulate this data. During the data gathering process, the accumulated data is sampled at a rate set by a frequency modulated ("chirper") phase-locked loop in order to remove undesirable data due to aliasing effects upon the digital filter. In this manner, an enhanced resolution of the gyroscope angular measurement is achieved.
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Patent Agency Ranking
公开(公告)号：FR2648556B1
公开(公告)日：1995-10-20
申请号：FR9004897
申请日：1990-04-17
Applicant: LITTON SYSTEMS INC
Inventor： TAZARTES DANIEL A , MARK JOHN G , EBNER ROBERT E
Abstract: A dither drive system for a ring laser gyroscope includes a computer, a digital to analog converter, a filter, and a power amplifier. The system senses the dither frequency of the gyro frame and produces a digital signal that corresponds to a specified dither drive signal and toggles the dither drive signal to drive the flexure at its resonant frequency. The dither drive system generates digital waveforms that approximate the sine function and digital waveforms that approximate the cosine function and applies the digital waveforms in quadrature to the flexure.
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公开(公告)号：FR2680241B1
公开(公告)日：1994-04-29
申请号：FR9209701
申请日：1992-08-05
Applicant: LITTON SYSTEMS INC
Inventor： MARK JOHN G , TAZARTES DANIEL A
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公开(公告)号：GB2254184A
公开(公告)日：1992-09-30
申请号：GB9200476
申请日：1992-01-10
Applicant: LITTON SYSTEMS INC
Inventor： MARK JOHN G , TAZARTES DANIEL A
IPC: G01C19/66
Abstract: A ring laser gyro having a ring laser that preferably has four legs and four corner mirrors. At least one of the corner mirror is partly transmissive, and the transmitted beam is sensed and converted into a digital signal. The digital signal is fed back in two computer loops to at least one digital-to-analog converter, and thence to a transducer which drives at least one corner mirror inward and outward. One of the computer loops includes a stepped demodulator having four steps per cycle. The steps have voltages at the operating voltage of the transducer, that voltage plus an increment, the operating voltage, and that voltage less a decrement. The first loop sends an operating voltage to the digital-to-analog converters. The second loop demodulates the beam signal at a second harmonic of the demodulation of the first loop to produce a voltage signal which controls the amplitude of dithering of the movable mirrors. A stepped modulator, in synchronism with the demodulator of the first loop, delivers a modulation signal to the digital-to-analog converters to step the movable mirrors. The operating voltage moves the mirrors into a position wherein the laser cavity operates at its intensity mode peaks.
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公开(公告)号：DE69733301T2
公开(公告)日：2006-02-02
申请号：DE69733301
申请日：1997-10-28
Applicant: LITTON SYSTEMS INC
Inventor： MARK JOHN G , TAZARTES DANIEL A
IPC: G01C21/16
Abstract: The invention is a method and apparatus for compensating for sculling in a strapdown inertial navigation system. The method operates on a sequence of inputs DELTA VB(n) derived at times n DELTA t from the outputs of one or more accelerometers. Separately compensated quantities DELTA VBc(m,p) calculated at times (pJ+1/2 ) DELTA t for M values of m are obtained by summing A(m,k) DELTA VB(pJ-j-k) over k from 0 to K-1 and over j from 0 to J-1 where the constants A(m,k) are chosen to minimize sculling error in the individual DELTA VNc(m,p) quantities where DELTA VNc(m,p) is the representation of DELTA VBc(m,p) in the navigation frame of reference. The final compensated quantity DELTA VBc(p) is obtained by summing B(m) DELTA VBc(m,p) over m where the constants B(m) are chosen to minimize sculling error in DELTA VNc(p) where DELTA VNc(p) is the representation of DELTA VBc(p) in the navigation frame of reference.
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公开(公告)号：DE69921948T2
公开(公告)日：2005-11-24
申请号：DE69921948
申请日：1999-12-09
Applicant: LITTON SYSTEMS INC
Inventor： TAZARTES DANIEL A , TIPTON HOWELL J
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