Honeywell G.m.b.h.

Honeywell International Inc.

Other

Joseph E Killpatrick

Dale F Berndt

Keith R Fritze

Timothy J Callaghan

Rodney H Thorland

Glen Aaron Sanders

William P Platt

Steven C Albers

Wesley C Sewell

John R Morrison

Bruce A Seiber

Joel G Hanse

Lloyd W Priddy

Theodore W Broberg

Charles R McClary

Stephen P Callaghan

Leroy O Thielman

Robert W Derry

Gregory E Cary

Ralph D Ormsby

Lawrence B Ehlert

A method and apparatus for correction of laser gyro dither pickoff signals. Dither pickoff signals are sampled during the dither input signal cycle at points where error is more prevalent in the dither pickoff signal. The samples are then used to modify correction factors used in the calculation of a corrected dither pickoff signal.

Dither stripper with non-linearity correction

A ring laser gyroscope or other motion sensor is dithered at a first rate if a global positioning signal is available and/or when alignment is not being performed, and is dithered at a second rate if a global positioning signal is not available and/or when alignment is being performed. The second rate is greater than the first rate.

Dither system for motion sensors

A ring laser gyroscope (RLG) employs an offset aperture for attenuating undesired modes of laser propagation therein. The RLG includes a block having a ring laser cavity containing a lasing gas, the cavity being substantially in the shape of a polygon having at least three sides and at least three vertices formed by the intersection of sides of the polygonal cavity. At least three mirrors are provided, equal in number to the number of vertices and positioned at the vertices to create a resonant ring laser having a polygonal ring path in the shape of the polygon. An aperture is provided in the ring laser cavity for attenuating undesired modes of laser propagation in the polygonal ring path of the laser. The aperture has an axis that is horizontally offset from a central axis of the polygonal ring path of the laser.

Ring laser gyroscope with offset aperture

A dither control system for a laser gyro having a dither motor for dithering the laser gyro through a desired angular displacement, known as the command angle, in response to a drive signal. In order to help avoid saturation of the laser gyro, the dither control system reduces the command angle by command angle reduction data when the average drive signal applied to the dither motor exceeds a maximum drive value until the command angle reduction data reaches zero. The command angle reduction value is calculated by integrating the difference between the average drive signal and the maximum drive value.

Dither control system for a ring laser gyro

Plasma is placed in ring laser gyro blocks to create laser beams for the operation of the ring laser gyro. The plasma is doped with a small portion of material that allows the ring laser gyro to operate for a long period of time.

Extending RLG lifetime by maintaining low level oxygen impurity background

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.

Modular laser gyro

A laser gyro lifetime prediction method incorporates a memory model that stores a worst case performance parameter for a readout intensity, a laser intensity and a derived quantity known as volts per mode for a laser gyro. A microprocessor based life prediction method utilizes a predetermined failure criteria to judge a estimate of laser gyro life based on historic performance of laser gyro operating parameters. The prediction is based on a linear quadratic or higher order fit of lifetime data for critical temperatures. The performance data is stored in a memory model for each critical temperature and parameter. The laser gyro reports eminent failures to the inertial navigation system or a host controller. Routine scheduled maintenance of the laser gyro is enhanced by knowing its lifetime.

Laser gyro life prediction

Apparatus for improving the bias stability of a ring laser gyro by selecting a secondary transverse mode and controlling the path length of the gyro to maintain the selected mode.

Transverse mode selected operation for a ring laser

A power control system for a ring laser gyro including a beam intensity readout. A monitor is coupled to the beam intensity readout for generating an intensity signal indicative of the intensity of the beam at an intensity signal output. A signal averager is coupled to the intensity signal output, the signal averager providing an average intensity signal at an average intensity signal output. An analog-to-digital convertor is coupled to the average intensity signal output for converting the average intensity signal output to a digital signal on a digital signal output. A processor is coupled to the digital signal output and generates a power control signal on a power control line in response to and in proportion to the value of the digital signal. A power supply is coupled at a programmable input to the power control line where the power supply means outputs a voltage signal on a voltage supply line coupled to a ring laser gyro electrode, where the voltage signal is responsive to the power control signal and the processor and power supply operate together so as to control a voltage signal in response to variations in beam intensity.

Microprocessor controlled anglaser gyropower control system

A sampling method and apparatus for sampling a dither signal includes the step of sensing a number of peak amplitudes P.sub.1, P.sub.2, P.sub.3 . . . P.sub.n each of the number of peak amplitudes having a corresponding times t.sub.1, t.sub.2, t.sub.3 . . . t.sub.n while simultaneously sensing a number of ring laser gyro output angles at each of the corresponding times t.sub.1, t.sub.2, t.sub.3 . . . t.sub.n. A value of the gyro net output, .DELTA..phi., is calculated as .DELTA..phi.=(.phi..sub.n -.phi..sub.n-1)-(.alpha..sub.n -.alpha..sub.n-1)K, where K is a correction factor. Alternatively, the stripped gyro angle output may be calculated as .phi..sub.g =.phi..sub.n -.alpha..sub.n K. Where .phi..sub.g is substantially equivalent to the sum of all of the changes in the stripped gyro angle, that is the sum of all .DELTA..phi.'s. The correction may include corrections for gain, phase angle, nonlinearity, temperature bias and scale factors.

Laser gyro dither strippr gain correction method and apparatus

A laser digital path length control method and apparatus for precisely controlling a laser path length to obtain a laser mode and change a laser mode. The invention uses a microprocessor to control a path length control circuit that continuously adjusts the position of path length control mirrors. The mirrors may be positioned in response to the microprocessor to acquire a particular mode of the laser or change the mode of the laser. While the gyro mode is changed the microprocessor increases the gyro run current to prevent loss of gyro function returning the current to its normal value following the mode change. The microprocessor adjusts the position of the two path length control mirrors such that total path length follows a predetermined or dynamic range. The invention allows the calculation of volts per mode of the laser by providing a means to monitor laser intensity as a function of voltage supplied to the laser path length controllers. The method and apparatus of the invention may be used in a laser gyro to improve system path length control and to help compensate for changes in system component parameters.

Laser gyro microprocessor based smart mode acquisition and high

A ring laser gyro bias drift improvement method and apparatus for compensating for periodic bias drift including a microprocessor which controls a path length control circuit that continuously adjusts the position of path length control mirrors. The mirrors are stepped through a range of positions that represent two laser modes. The microprocessor adjusts the position of the two path length control mirrors such that total path length remains constant. The invention improves bias drift by forcing the laser gyro system to operate at varying path length control positions. Each position has a varying bias that was shown to be periodic over two laser modes. By operating the laser system over a range of two laser modes the periodic bias error of the laser gyro is cancelled out over time.

Ring laser gyro bias drift improvement method and apparatus

An active current control apparatus for a ring laser gyro includes an apparatus for generating a control signal representative of a current value, such as, for example a microprocessor controller. Apparatus for supplying actively controlled current to the anode of the ring laser gyro in response to the control signal is coupled to the control signal so as to provide a constant current in the ring laser gyro beam path.

Active current control apparatus

A laser gyro configuration and control using a microprocessor. The microprocessor has a high speed peripheral transaction system which communicates through a high speed Universal Asynchronous Receiver Transmitter (UART) to a serial to parallel converter through a five Byte first in first out (FIFO) to an external system processor. The external system processor sends information in a serial fashion through a single byte parallel to serial converter to the high speed UART. Various information including gyro parameter load commands, gyro control commands, gyro status commands, and gyro calibration and diagnostic commands are sent over channels. The system provides a high speed method of controlling the laser gyro and configuring it with a processor with serial transmit and receive lines.

Laser gyro microprocessor configuration and control

A laser gyro built in test apparatus. A laser gyro includes a microprocessor which provides a high speed method of communicating test data to an external inertial navigation system. The microprocessor performs tests on the gyro including temperature sensor tests, dither drive tests, active current control tests, and reports on the expected life of the gyro. The gyro can be commanded from the external system to perform any number of the built in test functions. The built in test functions are periodically executed to evaluate the health of the laser gyro and are thereby incorporated in the monitor control loop of the laser gyro.

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Minneapolis, MN, United States of America

Joseph E Killpatrick