WO1995014906B1 - Modular laser gyro - Google Patents
Modular laser gyroInfo
- Publication number
- WO1995014906B1 WO1995014906B1 PCT/US1994/013689 US9413689W WO9514906B1 WO 1995014906 B1 WO1995014906 B1 WO 1995014906B1 US 9413689 W US9413689 W US 9413689W WO 9514906 B1 WO9514906 B1 WO 9514906B1
- Authority
- WO
- WIPO (PCT)
- Prior art keywords
- output
- dither
- digital
- gyro
- control
- Prior art date
Links
- 238000002789 length control Methods 0.000 claims 18
- 230000001276 controlling effect Effects 0.000 claims 12
- 230000000051 modifying Effects 0.000 claims 12
- 230000004044 response Effects 0.000 claims 8
- 238000006073 displacement reaction Methods 0.000 claims 6
- 238000006243 chemical reaction Methods 0.000 claims 4
- 230000000875 corresponding Effects 0.000 claims 2
- 230000003862 health status Effects 0.000 claims 2
- 238000005259 measurement Methods 0.000 claims 2
- 230000001702 transmitter Effects 0.000 claims 2
- 238000000034 method Methods 0.000 claims 1
- 230000002093 peripheral Effects 0.000 claims 1
- 230000002708 enhancing Effects 0.000 abstract 1
Abstract
A modular laser gyro incorporating a laser gyro with a digital control processor. The digital control processor safely and quickly starts the laser gyro. The microprocessor also executes tests on the gyro and provides a health signal. Optional start-up operations may be performed including the calibration of volts per mode and system configuration. Various information including gyro parameter load commands, gyro control commands, gyro status commands, and gyro calibration and diagnostic commands may be provided to an inertial navigation system. A high voltage start circuit includes a high voltage start module and high voltage pulse generator apparatus. The high voltage start circuit is contained within a modular laser gyro housing. A direct digital dither drive for a dither motor controls the dithering of the gyro to prevent lock in of the laser beams. A dither stripper controls the stripping of the dither signal. A bias drift rate improvement system, as well as a random drift rate improvement system reduces errors. A lifetime prediction mechanism incorporates a memory model that stores worst case performance parameters and evaluates them against predetermined failure criteria. An active current control controls lasing current to prolong life and enhance performance. A single transformer power supply powers the modular gyro.
Claims
AMENDED CLAIMS
[received by the International Bureau on 1 August 1995 (01.08.95);
original claims 9 and 28 cancelled; original claims 1, 17 and 18 amended;
remaining claims unchanged (8 pages)]
1. A modular sensor apparatus for measuring at least one inertial property, the
modular sensor apparatus comprising:
an inertial sensor means for sensing at least one inertial property, wherein the inertial sensor means has at least one sensor control input and a measured inertia} property output that varies in response to the at least one sensor control input; [and]
a digital control means for controlling the inertial sensor means, wherein the
digital control means has at least one control output connected to the at least one sensor control input, wherein the inertial sensor means and the digital control means are hermetically sealed in a housing, wherein the inertial sensor means is capable of being started with high voltage;
a low voltage power supply connection means for providing a hermetically sealed low voltage supply connection within the housing; and
a high voltage starting means for starting the inertial sensor means wherein the high voltage starting means is contained within the housing and is connected to the low voltage power supply connection means.
2. The modular sensor apparatus of claim 1 wherein the inertial sensor means
comprises a laser gyro.
3. The modular sensor apparatus of claim 1 wherein the digital control means further comprises a micro-controller. 4. The modular sensor apparatus of claim 1 further comprising an inertial sensor staπ up means connected to the inertial sensor means for start up of the inertial sensor means in a predetermined manner.
5. The modular sensor apparatus of claim 4 wherein the digital control means has at least one operating measurement output representing a health status for the modular sensor apparatus and the digital control means, further comprises a means for evaluating the health status connected to the at least one operating measurement output. 6. The modular sensor apparatus of claim 3 wherein the micro-controller further comprises a nonvolatile memory means, and wherein the micro-controller stores at least one operating parameter in the nonvolatile memory means.
7. The modular sensor apparatus of claim 6 further comprising at least one operating control input to set the modular sensor apparatus in at least one configuration, and wherein the modular sensor apparatus further comprises a configuration means for setting the modular sensor apparatus to the at least one configuration, wherein the configuration means has a configuration output connected to the at least one operating control input
8. The modular sensor apparatus of claim 1 further including a self test means for performing a built in test of the modular sensor apparatus, wherein the self test means is connected to the digital control means.
10. The modular sensor apparatus of claim 2 further comprising a direct digital dither drive apparatus for the laser gyro, wherein the laser gyro further comprises a dithered gyro block with a dither motor and a dither pickoff, the direct digital dither drive apparatus comprising:
means for sensing the dither pickoff connected to the dither pickoff and having a dither pickoff output;
means for amplifying the dither pickoff output having an amplified dither pickoff output;
means for analog to digital conversion connected to the amplified dither pickoff output having a digital dither signal output;
means for digital control connected to the digital dither signal output having a pulse width modulated signal output wherein the digital control means generates the pulse width modulated signal output in proportion to the digital dither signal output minus a reference displacement plus a predetermined amount of random noise; and
means for driving the dither motor in response to the pulse width modulated signal output having a dither drive signal connected to the dither motor.
11. The modular sensor apparatus of claim 2 further comprising a dither stripper apparatus for the laser gyro, the laser gyro further comprising a dithered gyro block with a dither motor and a dither pickoff, wherein the dither stripper apparatus comprises:
means for sensing the dither pickoff connected to the dither pickoff and having a dither pickoff output;
means for amplifying the dither pickoff output having an amplified dither pickoff output;
means for analog to digital conversion connected to the amplified dither pickoff output having a digital dither signal output; and
means for digital control connected to the digital dither signal output having a dither stripped inertial navigation output wherein the digital control means converts the digital dither signal output to an angular displacement value, generates a change in angular displacement by subtracting the angular displacement value from a previous angular displacement value, generates a change in readout counter value by reading a new readout counter value and subtracting from the new readout counter value a previous readout counter value, and generating the dither stripped inertial navigation output to be the difference between the change in angular displacement and the change in readout counter value.
12. The modular sensor apparatus of claim 2 further comprising a bias drift rate
improvement apparatus for the laser gyro, wherein the laser gyro further comprises a laser with a path length, a first path length control minor with a first mirror position, a second path length control mirror with a second mirror position, and a bias drift rate that varies periodically with the first mirror position and the second mirror position, wherein the bias drift rate improvement apparatus comprises:
a first mirror positioning means coupled to the first path length control mirror for positioning the first path length control mirror;
a second mirror positioning means coupled to the second path length control
mirror for positioning the second path length control mirror, and a control means for controlling the first mirror positioning means and the second mirror positioning means, the control means being coupled to the first mirror positioning means and second mirror positioning means such that the first minor position and second mirror position change over one period of the path length volts per mode.
13. The modular sensor apparatus of claim 6, wherein the micro-controller further comprises a means for predicting when the modular sensor apparatus will fail based on the at least one operating parameter. 14. The modular sensor apparatus of claim 1 wherein the inertial sensor means has an inertial sensor lifetime, the modular sensor apparatus further comprising a lifetime estimation means for determining the inertial sensor lifetime, wherein the lifetime estimation means is connected to the digital control means and wherein the lifetime estimation means has a lifetime output.
15. The modular sensor apparatus of claim 2 further comprising an active current control apparatus for the laser gyro comprising:
means for generating a digital control signal representative of a current value; means, coupled to the digital control signal generating means, for translating the digital control signal into an analog signal; and
means, coupled to the analog signal, for supplying driving current to an anode of the modular sensor apparatus in response to the analog signal and in proportion to the digital control signal.
16. The modular sensor apparatus of claim 2 comprising an active current control apparatus for the laser gyro further comprising a laser with a path length and a wavelength and an intensity, a first path length control mirror and a second path length control mirror, the modular sensor apparatus further comprising:
a digital logic means for providing a plurality of modulation signals including a
SWEEP signal, a SWITCH signal, a NOTSWITCH signal, a DITHER signal, and a NOTDITHER signal;
a first invertor means coupled to the digital logic means at a first input and
including an output;
means for switching coupled at a signal input to the output of the first invertor means, coupled at a first control input to the SWITCH signal and coupled at a second control input to the NOTSWITCH signal, wherein the means for switching has a first output corresponding to a first switch position and a second output corresponding to a second switch position;
means for integrating coupled at a first input to a first switching means output, coupled at a second input to a second switching means output, and including an output providing a path length control signal; means for monitoring laser beam intensity and providing a laser beam intensity monitor (LIM) signal;
means for controlling the digital logic means, including means for providing a pulse width modulated signal, a first analog-to-digital input, and a second analog-to-digital input, .wherein the controlling means is coupled at a logic control output to a control input of the digital logic means, wherein the controlling means is coupled at the first analog-to-digital input to the path length control signal, wherein the means for controlling the digital logic means is coupled at the second analog-to-digital input to the LIM signal, wherein the controlling means provides control signals to the digital logic means to operate the plurality of modulating signals in response to the path length control signal, wherein the controlling means further determines a
pulse width modulation duty cycle range for a pulse width modulation signal in response to the path length control signal and the LIM signal; and means, coupled to the means for providing a pulse width modulated signal and coupled to the path length control signal, for differentially driving the first path length control mirror and the second path length control mirror in response to the pulse width modulation signal.
17. The modular sensor apparatus of claim 1 wherein the high voltage starting means further comprises:
a DC voltage supply means having a voltage supply output; and
a DC to DC converter means connected to the voltage supply output to provide at least one high voltage power supply output.
18. The modular sensor apparatus of claim 1 wherein the high voltage starting means further comprises:
a transformer means having a first and second low voltage center-tapped windings connected to a low voltage supply; and
a first and second high voltage center-tapped windings providing a first and a second high voltage output.
19. The modular sensor apparatus of claim 2 in which at least one laser beam is
generated by a current flowing in at least a portion of a cavity between an anode and a cathode, an active current control system comprising in combination:
monitor means to generate a monitor signal indicative of a beam intensity;
power supply means coupled to the anode and the cathode to supply the current; and
means responsive to the monitor signal to control the current to maintain the beam intensity constant 20. The modular sensor apparatus of claim 1 further comprising a self test apparatus comprising:
a microprocessor with a high speed universal asynchronous receiver transmitter
(UART) and a peripheral transaction system controlling the UART;
a transmit line connected to the UART;
a receive line connected to the UART;
a microprocessor controller external system;
a serial to parallel converter connected to the transmit line to convert serial data on the transmit line to parallel data having a parallel output;
a first in first out (FIFO) register means connected to the parallel output having an interface output;
an interface logic unit connected to an output of the FIFO register means
connected to the microprocessor controller external system to receive commands from the microprocessor controller external system; and a parallel to serial converter connected to the interface logic unit and the receive line to convert parallel data from the interface logic unit to serial data for communication to the UART. 21. A modular laser gyro having a laser within a cavity within a gyro block, a
photodiode means connected to the gyro block to detect the laser, a dither drive motor connected to the gyro block to drive the gyro block, a dither pickoff connected to the gyro block to sense motion of the gyro block, and a cathode and a first and a second anode for maintaining the laser within the cavity, wherein the modular laser gyro further comprises:
a microcontroller connected to control the laser gyro having an A/D converter wherein the A/D converter is integral to the microcontroller and wherein the microcontroller has an active current control output to control cathode and anode current and a pulse width modulated output;
a direct digital dither drive connected to drive the dither drive motor and to receive the pulse width modulated output from the microcontroller, a path length control connected to control a PLC transducer means and connected to receive input from a PLC pickoff located on the gyro block and used for sensing laser path length wherein the path length control further has an A/D converter output used by the microcontroller to process laser path length data;
an active current control means connected to the laser gyro to maintain the laser within the gyro block having a microcontroller input, a first active current control output connected to the cathode, a second active current control output connected to the first anode, and a third active current control output connected to the second anode; and
means for high voltage start-up contained within a gyro housing and connected to the active current control means to allow for laser gyro start-up. 22. The modular laser gyro of claim 21 wherein the gyro block further comprises a block temperature sensor connected to the gyro block to measure block temperature wherein the block temperature sensor has an output connected to an A/D converter input.
23. The modular laser gyro of claim 21 wherein the microcontroller further comprises an universal asynchronous receiver transmitter (UART) which is integral to the microcontroller and connected through transmitting and receiving means to an external system used for controlling means for inertial sensing.
24. The modular laser gyro of claim 21 wherein the dither pickoff has a dither pickoff amplifier having a dither pickoff output connected to an A/D converter input. 25. The modular laser gyro of claim 21 wherein a readout for detecting the laser is connected to the laser gyro and has a photodiode means input, a readout output connected to an A/D converter input, and a readout output connected
simultaneously to a digital logic means and to ring laser gyros. 26. The modular sensor apparatus of claim 1 wherein the inertial sensor means
comprises a dithered laser gyro with a dither pickoff, wherein the dither pickoff has a dither pickoff output, the modular sensor apparatus further comprising: output to a first digital dither pickoff output; and
second analog to digital conversion means for converting the dither pickoff output to a second digital dither pickoff output.
27. The modular sensor apparatus of claim 26 wherein the second analog to digital conversion means is connected to the digital control means.
29. The modular sensor apparatus of claim 2 wherein the laser gyro further comprises a laser path having a laser path length, and a laser beam having a plurality of modes, wherein the digital control means further comprises a path length control register comprising a sweep up portion and a sweep down portion, and wherein the laser path length increases to one of the plurality of modes in response to the sweep up portion and the laser path length decreases to one of the plurality of modes in response to the sweep down portion.
30. A modular laser gyro comprising:
a modular laser gyro housing;
a laser gyro having a laser beam, and including laser gyro electrodes contained within die modular laser gyro housing, wherein the laser gyro generates a gyro angle;
a digital control processor having a current control output, a dither drive output, an onboard analog to digital convertor, and a microprocessor contained within the modular laser gyro housing;
an active current control means for controlling lasing current in the laser gyro, the active current control means having a control input connected to the current control output, the active current control means further including electrode outputs connected to die laser gyro electrodes and further including high voltage inputs, the active current control means being contained within the modular laser gyro housing;
a high voltage start circuit including a high voltage start module and high voltage pulse generator apparatus connected to the high voltage inputs wherein the high voltage start circuit is contained within the modular laser gyro housing;
means embedded in the digital control processor for calibrating volts per mode and system configuration;
a direct digital dither drive for controlling dithering of the laser gyro is connected to the dither drive output;
a dither pickoff means coupled to the onboard analog to digital convertor for transmitting a dither signal to the digital control processor; and a dither stripper means embedded in the digital control processor for receiving the dither signal and stripping the dither signal from the gyro angle.
Priority Applications (6)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| BR9408186A BR9408186A (en) | 1993-11-29 | 1994-11-29 | Modular laser gyroscope sensor apparatus and process of measuring random rate of deviation of laser gyroscope |
| KR1019960702817A KR960706629A (en) | 1993-11-29 | 1994-11-29 | Modular Laser Gyro |
| AU12139/95A AU699978B2 (en) | 1993-11-29 | 1994-11-29 | Modular laser gyro |
| EP95903173A EP0733196A1 (en) | 1993-11-29 | 1994-11-29 | Modular laser gyro |
| JP7515270A JPH09505668A (en) | 1993-11-29 | 1994-11-29 | Modular laser gyro |
| NO962183A NO962183L (en) | 1993-11-29 | 1996-05-29 | Module Laser Gyro |
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US16155593A | 1993-11-29 | 1993-11-29 | |
| US08/161,555 | 1993-11-29 |
Publications (3)
| Publication Number | Publication Date |
|---|---|
| WO1995014906A2 WO1995014906A2 (en) | 1995-06-01 |
| WO1995014906A3 WO1995014906A3 (en) | 1995-07-27 |
| WO1995014906B1 true WO1995014906B1 (en) | 1995-08-31 |
Family
ID=22581668
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| PCT/US1994/013689 WO1995014906A2 (en) | 1993-11-29 | 1994-11-29 | Modular laser gyro |
Country Status (11)
| Country | Link |
|---|---|
| US (1) | US6208414B1 (en) |
| EP (1) | EP0733196A1 (en) |
| JP (1) | JPH09505668A (en) |
| KR (1) | KR960706629A (en) |
| CN (1) | CN1145664A (en) |
| AU (1) | AU699978B2 (en) |
| BR (1) | BR9408186A (en) |
| CA (1) | CA2176752A1 (en) |
| IL (1) | IL111820A0 (en) |
| NO (1) | NO962183L (en) |
| WO (1) | WO1995014906A2 (en) |
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| US8781778B2 (en) * | 2011-09-30 | 2014-07-15 | Honeywell International Inc. | Systems and methods for thermal gradient compensation for ring laser gyroscopes |
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| US8901432B2 (en) | 2011-09-30 | 2014-12-02 | Honeywell International Inc. | Mitigation of block bending in a ring laser gyroscope caused by thermal expansion or compression of a circuit board |
| US20130088827A1 (en) * | 2011-10-07 | 2013-04-11 | Frontier Electronic Systems Corp. | Multi-Purpose Display Platform |
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| RU2731656C1 (en) * | 2019-07-31 | 2020-09-07 | Публичное акционерное общество "Московский институт электромеханики и автоматики" (ПАО "МИЭА") | Inertial measuring device with digital control device |
| CN111141267B (en) * | 2019-12-31 | 2021-10-22 | 中国船舶重工集团公司第七一七研究所 | Anti-interference method for jitter control system of mechanically jittered laser gyroscope |
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-
1994
- 1994-11-29 EP EP95903173A patent/EP0733196A1/en not_active Withdrawn
- 1994-11-29 AU AU12139/95A patent/AU699978B2/en not_active Ceased
- 1994-11-29 JP JP7515270A patent/JPH09505668A/en active Pending
- 1994-11-29 BR BR9408186A patent/BR9408186A/en not_active Application Discontinuation
- 1994-11-29 WO PCT/US1994/013689 patent/WO1995014906A2/en not_active Application Discontinuation
- 1994-11-29 CA CA002176752A patent/CA2176752A1/en not_active Abandoned
- 1994-11-29 KR KR1019960702817A patent/KR960706629A/en not_active Application Discontinuation
- 1994-11-29 IL IL11182094A patent/IL111820A0/en unknown
- 1994-11-29 CN CN94194915A patent/CN1145664A/en active Pending
-
1996
- 1996-05-29 NO NO962183A patent/NO962183L/en unknown
-
1997
- 1997-11-24 US US08/976,902 patent/US6208414B1/en not_active Expired - Lifetime
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