US20020186378A1 - Automatic gain control of a closed loop fiber optic gyroscope using non-linear control laws - Google Patents
Automatic gain control of a closed loop fiber optic gyroscope using non-linear control laws Download PDFInfo
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- US20020186378A1 US20020186378A1 US09/826,763 US82676301A US2002186378A1 US 20020186378 A1 US20020186378 A1 US 20020186378A1 US 82676301 A US82676301 A US 82676301A US 2002186378 A1 US2002186378 A1 US 2002186378A1
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- H—ELECTRICITY
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- H03G—CONTROL OF AMPLIFICATION
- H03G3/00—Gain control in amplifiers or frequency changers
- H03G3/20—Automatic control
- H03G3/30—Automatic control in amplifiers having semiconductor devices
- H03G3/3084—Automatic control in amplifiers having semiconductor devices in receivers or transmitters for electromagnetic waves other than radiowaves, e.g. lightwaves
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- This invention relates generally to signal processing in fiber optic gyroscope systems.
- This invention relates particularly to automatic gain control (AGC) circuits in fiber optic gyroscope signal processing systems. Still more particularly, this invention relates to an AGC circuit that achieves a stable response irrespective of the actual gain level.
- AGC automatic gain control
- a closed-loop fiber optic gyroscope requires a high bandwidth, high performance signal processing scheme to capture the differential phase difference induced by the rotation rate.
- a description of the control loop is contained in U.S. Pat. No. 5,883,716, which issued to Mark and Tazartes on Mar. 16, 1999 and which is assigned to Litton Systems, Inc., assignee of the present invention. The disclosure of U.S. Pat. No. 5,883,716 is incorporated by reference into the present disclosure.
- an active gain control scheme is required. Loop gain variations are due to aging of the light source, variations in optical output or loss over the operating temperature range, and temperature sensitivity of electro-optic components such as photodetectors.
- the optical signal can vary by a significant amount from instrument to instrument due to component and manufacturing tolerances.
- the present invention overcomes the deficiencies of the prior art by providing a stable AGC response irrespective of the actual gain level.
- a phase modulator is connected between the perturbation injection circuit and the fiber optic gyro. The phase modulator is arranged to apply the perturbation to the fiber optic gyroscope so that the perturbation signal is superimposed on the gyro output.
- a variable gain amplifier is arranged to receive the electrical signals indicative of optical signal signals output from the fiber optic gyroscope and provide an amplified signal.
- a perturbation compensation circuit is arranged to apply perturbation compensation signals to signals output from the variable gain amplifier.
- the perturbation compensation circuit produces a compensated signal by reducing the magnitude of the perturbation in the amplified signal output from the variable gain amplifier.
- a gain error circuit is connected to the perturbation compensation circuit.
- the gain error circuit produces a gain error signal that indicates the magnitude of the perturbation signal remaining in the amplified signal after perturbation compensation.
- a system processor is connected between the gain error circuit and the variable gain amplifier.
- the system processor provides a gain control signal to the variable gain amplifier to reduce the magnitude of the gain error signal.
- Processing circuitry is connected between the perturbation compensation circuit and the phase modulator for determining the rotation rate sensed by the fiber optic gyroscope and for controlling the phase modulator to apply a rate nulling signal to the fiber optic gyroscope.
- FIG. 1 is a simplified block diagram of a fiber optic gyroscope system that includes automatic gain control circuitry according to the present invention
- FIG. 2 is a block diagram of the primary loop of the fiber optic gyroscope system of FIG. 1;
- FIG. 3 is a block diagram of an algorithm that may be included in the present invention.
- a fiber optic rotation sensor system 10 includes a fiber optic gyroscope 12 that includes a fiber optic sensing coil (not shown) that detects rotations about a sensing axis perpendicular to the plane of the sensing coil by means of the well-known Sagnac effect.
- the fiber optic gyroscope 12 produces an optical signal of fluctuating intensity determined by interference between counter-propagating waves in the sensing coil.
- the interference pattern indicates the rate of rotation of the sensing coil about its sensing axis.
- the present invention includes a perturbation injection circuit 14 that provides a perturbation signal to a modulator 16 .
- the modulated perturbation signal is then input from the modulator 16 to the fiber optic gyroscope 12 .
- the modulated perturbation signal is superimposed on the optical signal produced by the fiber optic gyroscope 12 in accordance with the Sagnac effect.
- the signal output from the fiber optic gyroscope 12 is incident upon a photodetector 18 , which produces an analog electrical signal that indicates the intensity of the optical output from the fiber optic gyroscope 12 .
- the electrical signal from the photodetector 18 is then amplified by a variable gain amplifier 20 .
- the amplified analog signal is input to an analog to digital (A/D) converter 22 that produces a digital signal that is used in further processing of the output of the fiber optic gyroscope 12 .
- A/D analog to digital
- the digital signal output from the A/D converter 22 is input to a compensation circuit 24 that compensates for the injected perturbation.
- the output of the compensation circuit 24 is input to a rate demodulation processing circuit 26 and to a demodulator 28 .
- the rate demodulation processing circuit 26 determines the rotation rate.
- a signal indicative of the rotation rate is output by the rate demodulation processing circuit 26 and input to a gyro control loop and modulation control circuit 30 .
- the fiber optic rotation sensor 10 is arranged in the well-known phase nulling configuration. Accordingly, the gyro control loop and modulation control circuit 30 provides a signal to the modulator 16 that nulls the phase shift in the sensing coil caused by the Sagnac effect.
- the demodulator 28 detects errors in the gain of the variable gain amplifier 20 .
- a digital signal that indicates gain errors is input to a linearization and integration circuit 32 , which provides the linearized and integrated gain error signal to a digital to analog (D/A) converter 34 .
- the D/A converter 34 then provides the analog gain error signal to the gain control input of the variable gain amplifier 20 .
- the AGC function is accomplished by injecting a know perturbation ⁇ d in the loop and demodulating the resulting compensated signal with appropriate signs based on the polarity of the compensation.
- variable gain amplifier 20 used in the present invention employs a variable gain element whose gain in dB is proportional to the control voltage.
- Prior designs used a linear amplifier (not shown).
- the non-linear characteristic provided by the variable gain amplifier 20 is used advantageously in the gain control loop.
- FIG. 2 is a more detailed block diagram of the AGC system according to the present invention.
- the fiber optic gyro 12 is responsive to the sum of the Sagnac phase shift and the phase shift produced by the modulator 16 .
- a summing junction 40 receives a signal input from the phase modulator 16 and a signal (SSF) ⁇ that represents the phase shift induced by the angular rate ⁇ where SSF is the Sagnac scale factor of the fiber gyro 12 .
- the summing junction 40 adds the signal received from the phase modulator 16 by the scale factor to produce a signal that is input to the fiber gyro 12 .
- the fiber gyro 12 uses the Sagnac effect to produce a signal I 0 /2 sin ⁇ M where ⁇ M is the phase difference between the modulated counter-propagating waves in the sensing coil.
- the optical signal output of the fiber gyro 12 is converted to an electrical signal by the photodetector 18 .
- the photodetector 18 has a scale factor K pd which relates the electrical current output from the photodetector 18 to the optical power incident thereon.
- the photodetector output is then amplified by a transimpedance amplifier 42 that has a scale factor K TI .
- the transimpedance amplifier 42 is connected between the photodetector 18 and the variable gain amplifier 20 and serves to match the output impedance of the photodetector 18 to the input impedance of the variable gain amplifier 20 .
- the amplified electrical signal output from the variable gain amplifier 20 is input to a filter circuit 44 , which has scale factor k filt , that is preferably about 0.6.
- the signal output from the filter circuit 44 is input to the A/D converter 22 , which converts the analog electrical signals into digital signals that are used for processing the fiber gyro output and for AGC of the variable gain amplifier 20 .
- the digital signal output from the D/A converter 22 is input to a scaling circuit 46 .
- the A/D converter 22 and the scaling circuit 46 together have a scale factor K A that preferably is about 6554 bits/volt.
- the output of the scaling circuit 46 is input to a summing junction 24 which also receives an input signal ⁇ rd that is used for dither compensation. Signals output from the summing junction 24 are input to a rate loop control circuit 50 and to an AGC demodulator 52 .
- the rate loop control circuit 50 may include one or more integrators that operate on the signals.
- U.S. Pat. No. 5,883,716, which issued to Mark and Tazartes on Mar. 16, 1999 and assigned to Litton Systems, Inc., assignee of the present invention discloses a rate loop control circuit that may used as the rate loop control circuit in the present invention.
- the output of the rate loop control circuit 50 is input to a digital gain circuit 64 that applies a gain of 2 S to the output of the rate loop controller 50 .
- the output of the digital gain circuit 64 is input to a summing junction 66 , which applies the modulation by the dither signal ⁇ d.
- the output of the summing junction 66 is input to a summing circuit 68 that produces a ramp signal output that is input to a scaling circuit 70 .
- the scaling circuit 70 multiplies the ramp signal by 2 ⁇ 16 and provides an output signal to a multiplier 72 that also receives a signal to indicate the phase modulator scale factor PMSF. Signals output from the multiplier 72 are input to a D/A converter 76 , which converts the digital signal input thereto into an analog signal suitable for input to the phase modulator 16 .
- the dither compensated signal input to the AGC demodulator 52 is demodulated with the appropriate signs based on the polarity of the compensation.
- the demodulated signal is then input to an integrator 78 which in turn provides an output to a system processor 80 .
- the compensation ⁇ rd will exactly cancel the signal generated by the perturbation, and the demodulated value will be zero. If, however, the gain is in error, a residual signal will survive, which results in a non-zero demodulated value.
- the sign and magnitude of the demodulated value are indicative of whether the gain is high or low and by how much.
- the system processor 80 produces a gain control signal to adjust the gain accordingly to bring the residual signal to zero.
- the gain control signal from the system processor 80 is input to a gain control A/D converter, 82 , which, in turn, provides the analog gain control signal to the gain control input of the variable gain amplifier 20 .
- ⁇ is a constant and V is the voltage applied to the gain control input of the amplifier 20 .
- g 0 is the normalizing gain
- 20 ⁇ is the gain sensitivity in dB/volt.
- the gain control law may be rewritten to relate to the binary control word driving the D/A converter 34 , which in turn generates the control voltage. Accordingly, the gain is given by
- ⁇ is the digital control word written to the D/A converter 34 (for example 1 256 ⁇ 1 bit
- b is the number of bits in the binary control word (for example between 0 and 255 bits).
- the gain may also be expressed in dB using the following expression:
- [0034] is the AGC DAC scale factor in volts/bit.
- ⁇ D ⁇ ⁇ ⁇ T ⁇ ⁇ 2 - S ⁇ G L ⁇ ⁇ ⁇ ⁇ d ( 12 )
- ⁇ b is the error in the gain control D/A converter 34 .
- t c is the desired time constant for the AGC loop.
- t c is the desired time constant for the AGC loop.
- the value of ⁇ circumflex over ( ⁇ ) ⁇ should be limited in accordance with the gain range. For a 10 to 1 range, the limits are ⁇ 9.0 ⁇ circumflex over ( ⁇ ) ⁇ 0.9.
- FIG. 3 illustrates an algorithm of signal processing that may be used to control the gain of the amplifier 20 .
- ⁇ e ⁇ ⁇ ⁇ ⁇ T ⁇ 2 S G L ⁇ d ( 20 )
- ⁇ is the loop transit time
- ⁇ T is the demodulator integration time
- s is the loop controller shift count
- G L is the primary loop gain (1.0 for deadbeat control, 0.2 for integral control);
- d is the dither perturbation value.
- ⁇ AGC ⁇ ⁇ ⁇ T t c ⁇ 1 ⁇ ⁇ ⁇ ln ⁇ ⁇ ( 10 ) ( 21 )
- t c is the desired AGC loop time constant and (20) ⁇ is the variable gain amplifier sensitivity in dB/bit.
- the gain control command b is set to a value
- b init is the initial gain control D/A converter 34 command to be read from memory.
- ⁇ D is the demodulator output integrated over the interval ⁇ T.
- the limit of the estimated gain error ⁇ is limited to [ ⁇ 9.0, 0.9].
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Abstract
Description
- This invention relates generally to signal processing in fiber optic gyroscope systems. This invention relates particularly to automatic gain control (AGC) circuits in fiber optic gyroscope signal processing systems. Still more particularly, this invention relates to an AGC circuit that achieves a stable response irrespective of the actual gain level.
- A closed-loop fiber optic gyroscope requires a high bandwidth, high performance signal processing scheme to capture the differential phase difference induced by the rotation rate. A description of the control loop is contained in U.S. Pat. No. 5,883,716, which issued to Mark and Tazartes on Mar. 16, 1999 and which is assigned to Litton Systems, Inc., assignee of the present invention. The disclosure of U.S. Pat. No. 5,883,716 is incorporated by reference into the present disclosure. In order to achieve the high degree of performance required while accommodating wide variations in loop gain, an active gain control scheme is required. Loop gain variations are due to aging of the light source, variations in optical output or loss over the operating temperature range, and temperature sensitivity of electro-optic components such as photodetectors. In addition, the optical signal can vary by a significant amount from instrument to instrument due to component and manufacturing tolerances.
- Automatic gain control loops have therefore been utilized in the past to ensure that the total loop gain remains constant, which is essential to achieving maximum bandwidth and high order loop response. In the past, analog multipliers were used as gain stages in the detection path of the fiber optic gyroscope. While these devices provided an ideal linear control law (i.e. the gain is directly proportional to the applied control voltage), they exhibited a number of undesirable characteristics. These include bandwidth limitations, noise, cost, and linearity as a function of signal level.
- For high performance, low noise fiber optic gyroscopes, an alternate gain control block was therefore considered. This is a variable gain amplifier whose gain in dB is proportional to the applied control voltage. In essence, this implies that the gain of the amplifier is an exponential function of applied control voltage as opposed to a linear function as in the earlier embodiments. Such devices are now readily available and offer lower noise and of course, a wider range of gain adjustment without substantial degradation in signal gain linearity. A gain range of 10:1 is easily achievable with such a device.
- The desire to adapt such variable gain amplifiers in a fiber optic gyroscope circuit introduced a new problem which this invention addresses. Because of the non-linear gain control law, the time constant or response time of the AGC (automatic gain control) itself could be highly variable, thus limiting its ability to start-up rapidly and to track changes rapidly.
- The present invention overcomes the deficiencies of the prior art by providing a stable AGC response irrespective of the actual gain level.
- A closed loop gain control circuit according to the present invention for controlling the gain of a variable gain amplifier that is arranged to amplify electrical signals indicative of optical signal signals output from a fiber optic gyroscope comprises a perturbation injection circuit arranged to provide a perturbation signal ±d. A phase modulator is connected between the perturbation injection circuit and the fiber optic gyro. The phase modulator is arranged to apply the perturbation to the fiber optic gyroscope so that the perturbation signal is superimposed on the gyro output. A variable gain amplifier is arranged to receive the electrical signals indicative of optical signal signals output from the fiber optic gyroscope and provide an amplified signal. A perturbation compensation circuit is arranged to apply perturbation compensation signals to signals output from the variable gain amplifier. The perturbation compensation circuit produces a compensated signal by reducing the magnitude of the perturbation in the amplified signal output from the variable gain amplifier. A gain error circuit is connected to the perturbation compensation circuit. The gain error circuit produces a gain error signal that indicates the magnitude of the perturbation signal remaining in the amplified signal after perturbation compensation. A system processor is connected between the gain error circuit and the variable gain amplifier. The system processor provides a gain control signal to the variable gain amplifier to reduce the magnitude of the gain error signal. Processing circuitry is connected between the perturbation compensation circuit and the phase modulator for determining the rotation rate sensed by the fiber optic gyroscope and for controlling the phase modulator to apply a rate nulling signal to the fiber optic gyroscope.
- FIG. 1 is a simplified block diagram of a fiber optic gyroscope system that includes automatic gain control circuitry according to the present invention;
- FIG. 2 is a block diagram of the primary loop of the fiber optic gyroscope system of FIG. 1; and
- FIG. 3 is a block diagram of an algorithm that may be included in the present invention.
- Referring to FIG. 1, a fiber optic
rotation sensor system 10 includes a fiberoptic gyroscope 12 that includes a fiber optic sensing coil (not shown) that detects rotations about a sensing axis perpendicular to the plane of the sensing coil by means of the well-known Sagnac effect. The fiberoptic gyroscope 12 produces an optical signal of fluctuating intensity determined by interference between counter-propagating waves in the sensing coil. The interference pattern indicates the rate of rotation of the sensing coil about its sensing axis. - The present invention includes a
perturbation injection circuit 14 that provides a perturbation signal to amodulator 16. The modulated perturbation signal is then input from themodulator 16 to the fiberoptic gyroscope 12. The modulated perturbation signal is superimposed on the optical signal produced by the fiberoptic gyroscope 12 in accordance with the Sagnac effect. - The signal output from the fiber
optic gyroscope 12 is incident upon aphotodetector 18, which produces an analog electrical signal that indicates the intensity of the optical output from the fiberoptic gyroscope 12. The electrical signal from thephotodetector 18 is then amplified by avariable gain amplifier 20. The amplified analog signal is input to an analog to digital (A/D)converter 22 that produces a digital signal that is used in further processing of the output of the fiberoptic gyroscope 12. - The digital signal output from the A/
D converter 22 is input to acompensation circuit 24 that compensates for the injected perturbation. The output of thecompensation circuit 24 is input to a ratedemodulation processing circuit 26 and to ademodulator 28. - The rate
demodulation processing circuit 26 determines the rotation rate. A signal indicative of the rotation rate is output by the ratedemodulation processing circuit 26 and input to a gyro control loop andmodulation control circuit 30. The fiberoptic rotation sensor 10 is arranged in the well-known phase nulling configuration. Accordingly, the gyro control loop andmodulation control circuit 30 provides a signal to themodulator 16 that nulls the phase shift in the sensing coil caused by the Sagnac effect. - The
demodulator 28 detects errors in the gain of thevariable gain amplifier 20. A digital signal that indicates gain errors is input to a linearization andintegration circuit 32, which provides the linearized and integrated gain error signal to a digital to analog (D/A)converter 34. The D/A converter 34 then provides the analog gain error signal to the gain control input of thevariable gain amplifier 20. - The AGC function is accomplished by injecting a know perturbation ±d in the loop and demodulating the resulting compensated signal with appropriate signs based on the polarity of the compensation.
- The
variable gain amplifier 20 used in the present invention employs a variable gain element whose gain in dB is proportional to the control voltage. Prior designs used a linear amplifier (not shown). The non-linear characteristic provided by thevariable gain amplifier 20 is used advantageously in the gain control loop. - FIG. 2 is a more detailed block diagram of the AGC system according to the present invention. The fiber
optic gyro 12 is responsive to the sum of the Sagnac phase shift and the phase shift produced by themodulator 16. A summingjunction 40 receives a signal input from thephase modulator 16 and a signal (SSF)Ω that represents the phase shift induced by the angular rate Ω where SSF is the Sagnac scale factor of thefiber gyro 12. The summingjunction 40 adds the signal received from thephase modulator 16 by the scale factor to produce a signal that is input to thefiber gyro 12. Thefiber gyro 12 uses the Sagnac effect to produce a signal I0/2 sin φM where φM is the phase difference between the modulated counter-propagating waves in the sensing coil. The optical signal output of thefiber gyro 12 is converted to an electrical signal by thephotodetector 18. Thephotodetector 18 has a scale factor Kpd which relates the electrical current output from thephotodetector 18 to the optical power incident thereon. The photodetector typically has a scale factor Kpd=0.9 A/W. - The photodetector output is then amplified by a
transimpedance amplifier 42 that has a scale factor KTI. Thetransimpedance amplifier 42 is connected between thephotodetector 18 and thevariable gain amplifier 20 and serves to match the output impedance of thephotodetector 18 to the input impedance of thevariable gain amplifier 20. The amplified electrical signal output from thevariable gain amplifier 20 is input to afilter circuit 44, which has scale factor kfilt, that is preferably about 0.6. - The signal output from the
filter circuit 44 is input to the A/D converter 22, which converts the analog electrical signals into digital signals that are used for processing the fiber gyro output and for AGC of thevariable gain amplifier 20. The digital signal output from the D/A converter 22 is input to ascaling circuit 46. The A/D converter 22 and the scalingcircuit 46 together have a scale factor KA that preferably is about 6554 bits/volt. - The output of the scaling
circuit 46 is input to a summingjunction 24 which also receives an input signal ±rd that is used for dither compensation. Signals output from the summingjunction 24 are input to a rateloop control circuit 50 and to anAGC demodulator 52. - The rate
loop control circuit 50 may include one or more integrators that operate on the signals. U.S. Pat. No. 5,883,716, which issued to Mark and Tazartes on Mar. 16, 1999 and assigned to Litton Systems, Inc., assignee of the present invention discloses a rate loop control circuit that may used as the rate loop control circuit in the present invention. The output of the rateloop control circuit 50 is input to adigital gain circuit 64 that applies a gain of 2S to the output of therate loop controller 50. The output of thedigital gain circuit 64 is input to a summingjunction 66, which applies the modulation by the dither signal ±d. After the dither is introduced into the circuit, the output of the summingjunction 66 is input to a summingcircuit 68 that produces a ramp signal output that is input to ascaling circuit 70. The scalingcircuit 70 multiplies the ramp signal by 2−16 and provides an output signal to amultiplier 72 that also receives a signal to indicate the phase modulator scale factor PMSF. Signals output from themultiplier 72 are input to a D/A converter 76, which converts the digital signal input thereto into an analog signal suitable for input to thephase modulator 16. - The dither compensated signal input to the
AGC demodulator 52 is demodulated with the appropriate signs based on the polarity of the compensation. The demodulated signal is then input to anintegrator 78 which in turn provides an output to asystem processor 80. Ideally, if the forward gain of the fiber optic gyroscope signal path is correct, the compensation ±rd will exactly cancel the signal generated by the perturbation, and the demodulated value will be zero. If, however, the gain is in error, a residual signal will survive, which results in a non-zero demodulated value. The sign and magnitude of the demodulated value are indicative of whether the gain is high or low and by how much. Thesystem processor 80 produces a gain control signal to adjust the gain accordingly to bring the residual signal to zero. The gain control signal from thesystem processor 80 is input to a gain control A/D converter, 82, which, in turn, provides the analog gain control signal to the gain control input of thevariable gain amplifier 20. - The following mathematical analysis explains additional details of the method of operation of the AGC function provided by the present invention. The gain characteristic for the
amplifier 20 is given by - G(V)=
g 010αV, (1) - where α is a constant and V is the voltage applied to the gain control input of the
amplifier 20. - The gain expressed in dB is written as
- 20 log(G(V))=20 log(g 0)+20αV, (2)
- where g0 is the normalizing gain, and 20α is the gain sensitivity in dB/volt.
- Alternatively, the gain control law may be rewritten to relate to the binary control word driving the D/
A converter 34, which in turn generates the control voltage. Accordingly, the gain is given by - G(b)=g 010βb (3)
-
- ) and b is the number of bits in the binary control word (for example between 0 and 255 bits).
- The gain may also be expressed in dB using the following expression:
- 20 log (G(b))=20 log(g 0)+20βb, (4)
-
- is the AGC DAC scale factor in volts/bit.
-
-
- and
- r=G L·2−S. (7)
-
- Define the quantity G(b) as
- G(b)=G0(1−ε), (10)
- where ε is the gain error. Using Eq. (10) in Eq. (9) then gives the result that
- D=2−SGLβd. (11)
-
-
-
- where Δb is the error in the gain control D/
A converter 34. - Taking the natural logarithm of Eq. (14) gives
- 1n(1−ε)=βΔb1n(10). (15)
-
-
-
-
- where tc is the desired time constant for the AGC loop. In order to ensure stability of the above equations, the value of {circumflex over (ε)} should be limited in accordance with the gain range. For a 10 to 1 range, the limits are −9.0≦{circumflex over (ε)}≦0.9.
-
- where
- τ is the loop transit time;
- ΔT is the demodulator integration time;
- s is the loop controller shift count;
- GL is the primary loop gain (1.0 for deadbeat control, 0.2 for integral control);
- and
-
- where tc is the desired AGC loop time constant and (20)β is the variable gain amplifier sensitivity in dB/bit.
- The gain control command b is set to a value
- b=binit (22)
- where binit is the initial gain control D/
A converter 34 command to be read from memory. At the integration interval (i.e., every ΔT), - ε=KεΣD (23)
-
-
Claims (24)
Priority Applications (7)
Application Number | Priority Date | Filing Date | Title |
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US09/826,763 US6473182B1 (en) | 2000-07-27 | 2001-04-04 | Automatic gain control of a closed loop fiber optic gyroscope using non-linear control laws |
EP01957249A EP1310044B1 (en) | 2000-07-27 | 2001-07-25 | Automatic gain control of a closed loop fiber optic gyroscope using non-linear control laws |
DE60133291T DE60133291T2 (en) | 2000-07-27 | 2001-07-25 | AUTOMATIC GAIN CONTROL OF A FIBEROPTIC GYROSCOPE WITH CLOSED REGULATORY LOOP USING NONLINEAR REGULATIONS |
PCT/US2001/023437 WO2002011282A2 (en) | 2000-07-27 | 2001-07-25 | Automatic gain control of a closed loop fiber optic gyroscope using non-linear control laws |
AU2001279013A AU2001279013A1 (en) | 2000-07-27 | 2001-07-25 | Automatic gain control of a closed loop fiber optic gyroscope using non-linear control laws |
IL15389901A IL153899A0 (en) | 2000-07-27 | 2001-07-25 | Automatic gain control of a closed loop fiber optic gyroscope using non-linear control laws |
JP2002515699A JP3936658B2 (en) | 2000-07-27 | 2001-07-25 | Automatic gain control of closed-loop optical fiber gyroscope using nonlinear control method |
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US22129100P | 2000-07-27 | 2000-07-27 | |
US09/826,763 US6473182B1 (en) | 2000-07-27 | 2001-04-04 | Automatic gain control of a closed loop fiber optic gyroscope using non-linear control laws |
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US20020186378A1 true US20020186378A1 (en) | 2002-12-12 |
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EP (1) | EP1310044B1 (en) |
JP (1) | JP3936658B2 (en) |
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US5684589A (en) * | 1995-08-28 | 1997-11-04 | Litton Systems, Inc. | Loop controller for fiber optic gyro with distributed data processing |
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2001
- 2001-04-04 US US09/826,763 patent/US6473182B1/en not_active Expired - Lifetime
- 2001-07-25 JP JP2002515699A patent/JP3936658B2/en not_active Expired - Lifetime
- 2001-07-25 WO PCT/US2001/023437 patent/WO2002011282A2/en active Application Filing
- 2001-07-25 IL IL15389901A patent/IL153899A0/en unknown
- 2001-07-25 EP EP01957249A patent/EP1310044B1/en not_active Expired - Lifetime
- 2001-07-25 AU AU2001279013A patent/AU2001279013A1/en not_active Abandoned
- 2001-07-25 DE DE60133291T patent/DE60133291T2/en not_active Expired - Lifetime
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Also Published As
Publication number | Publication date |
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EP1310044A2 (en) | 2003-05-14 |
DE60133291D1 (en) | 2008-04-30 |
IL153899A0 (en) | 2003-07-31 |
EP1310044B1 (en) | 2008-03-19 |
US6473182B1 (en) | 2002-10-29 |
WO2002011282A3 (en) | 2003-03-13 |
DE60133291T2 (en) | 2009-04-23 |
JP2004516695A (en) | 2004-06-03 |
AU2001279013A1 (en) | 2002-02-13 |
WO2002011282A2 (en) | 2002-02-07 |
JP3936658B2 (en) | 2007-06-27 |
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