| Class / Patent application number | Description | Number of patent applications / Date published |
|---|
| 356472000 | Lock-in prevention | 8 |
| 20110194119 | SOLID-STATE LASER GYRO OPTICALLY ACTIVE THROUGH ALTERNATING BIAS - The field of the invention is that of solid-state laser gyros used for the measurements of rotation speed or relative angular positions. This type of equipment is notably used for aeronautical applications. The object of the invention is to complete the optical devices necessary to control the instability of lasers by specific optical devices enabling elimination of the dead zone and of population inversion gratings exiting in the amplifying medium. An “all optical” solid-state laser is hence obtained without moveable parts, stable and without a dead zone. To this end, the laser gyro according to the invention comprises notably and optical assembly enabling a nonreciprocal optical phase-shift to be introduced between the counterpropagating modes; and control means allowing the phase-shift amplitude to be varied periodically around a mean value that is very approximately zero. | 08-11-2011 |
| 20160138922 | ELIMINATING RING LASER GYRO BACKSCATTER - A ring laser gyroscope (RLG) block is provided. The RLG block includes a first corner bordered by a first portion of a first side and a first portion of a third side; a second corner bordered by a first portion of a second side and a second portion of the third side; and a third corner bordered by a second portion of the second side and a second portion of the first side. The first portion of the first side shifts the first corner laterally in a lasing plane of the RLG block, toward the second corner, and perpendicular to a first normal of a first mirror when a temperature change contracts the RLG block; and shifts the first corner laterally away from the second corner, and perpendicular to the first normal when the temperature change causes an expansion of the ring laser gyroscope block. | 05-19-2016 |
| 356473000 | Path length control (PLC) | 3 |
| 20100014092 | GYROSCOPE MODE SHIFT DETECTION AND SCALE FACTOR COMPENSATION - A method for maintaining measurement accuracy of a ring laser gyroscope is disclosed. The method involves periodically measuring a path length control voltage in the ring laser gyroscope over a prescribed temperature range. When a first path length controlled by the path length control voltage deviates at least one wavelength from a nominal path length, the method detects the change in the path length as a mode shift. For each mode shift, the method applies a path length correction to maintain the first path length at a target path length over the prescribed temperature range. The method can apply a correction to a measurement signal output of the ring laser gyroscope by adjusting a calibrated scale factor depending on an actual integer number of wavelengths achieved during a mode shift. | 01-21-2010 |
| 20110116097 | METHOD FOR POSITIONING THE MIRRORS OF A TRIPLE AXIS LASER GYROMETER, IN PARTICULAR WHEN STARTING THE GYROMETER - In a method for positioning three translatable mirrors in a device that includes three laser cavities arranged in a ring, each of the three laser cavities includes an optical amplification medium that can be excited to generate light waves. Each of the three laser cavities also includes an optical cavity formed by a set of mirrors including two of the translatable mirrors, the length of the optical cavity depending on the position of the two translatable mirrors, wherein the two translatable mirrors can be moved within position ranges imparting to the optical cavity lengths at which the amplification medium generates at least one laser wave. Each of the three translatable mirrors is used in the formation of two of the three optical cavities. The method includes the phase of prepositioning the three mirrors at an initial triplet of predetermined respective positions. The method also includes the phase of simultaneously moving in translation the three mirrors within ranges having a same amplitude that is lower than or equal to the intermode of the optical cavity having the highest intermode, to ensure that each of the optical cavities has a length for which the amplification medium provides a maximum gain. The intensities of the laser waves flowing respectively through each of the optical cavities are measured for each triplet of positions assumed by the mirrors. The method also includes the phase of determining, from the three triplets of mirror positions that respectively allowed each of the three cavities to provide a maximum intensity, the length of each of the three cavities at which the cavity provides a maximum intensity. The method further includes the phase of determining a single final triplet of mirror positions for simultaneously imparting to the three lengths at which they provide a maximum intensity. The method also includes the phase of positioning the mirrors according to the final position triplet. The invention can be used in positioning and navigation. | 05-19-2011 |
| 20120026502 | VARIABLE PATH LENGTH CONTROL MODULATION FREQUENCY - A gyroscope system comprises a gyroscope block having a plurality of cavities and a plurality of passages that define a path; a plurality of mirrors each located in one of the plurality of cavities; at least one mirror drive coupled to one of the plurality of mirrors and configured to change a position of the respective mirror, wherein the path's length is changed by the change in the position of the respective mirror; a dither system coupled to the gyroscope block and configured to induce an angular rotation of the gyroscope block; and a controller configured to provide a dither signal indicative of a dither frequency to the dither system and a path length control (PLC) signal indicative of a PLC frequency to the at least one mirror drive. The controller is configured to calculate the PLC frequency as a function of the dither frequency. | 02-02-2012 |
| 356475000 | Having dither signal control | 2 |
| 20130083329 | RATE SENSITIVE BLANKING OF A PATH LENGTH CONTROL CIRCUIT IN A GYROSCOPE - A method and system for rate sensitive blanking in a path length control circuit of a gyroscope is provided. The method comprises determining an angular rate of the gyroscope, detecting a zero rate of the gyroscope where one or more single beam signals occur, and determining one or more blanker positions based on the zero rate. A blanker pulse is generated at the blanker positions such that the path length control circuit suspends operation when the one or more single beam signals occur. | 04-04-2013 |
| 20140300899 | RING LASER GYRO - A ring laser gyro with no piezoelectric elements for dither detection includes a laser beam receiving unit for receiving a laser beam taken out of a gyro block, a laser beam intensity measuring unit for measuring the intensity of the laser beam received by the laser beam receiving unit, a dither mechanism, a dither control unit for driving the dither mechanism, and a gyro case housing the gyro block, wherein the laser beam receiving unit is secured to the gyro case, the laser beam receiving unit has a laser beam receiving surface for receiving the laser beam from the gyro block to detect a laser beam receiving position on the laser beam receiving surface and output positional information indicating the laser beam receiving position. The dither control unit drives the dither mechanism on the basis of information indicating the amplitude of the laser beam receiving position obtained from the positional information. | 10-09-2014 |
| 356476000 | By dithering (suspensions, drives, flexures) | 1 |
| 20110249269 | Device for Digitally Processing Information Obtained from a Gyrolaser and Associated Gyrolaser - A gyrolaser with optical cavity includes a plurality of mirrors, at least one photo-detector delivering two optical signals in phase quadrature, said signals being digitized, means for controlling the position of one of said mirrors by conversion of an electrical signal into a mechanical force, means for activating said gyrolaser in an oscillatory movement by conversion of an oscillation electrical signal into a mechanical force and means for measuring the angular velocity of said gyrolaser, and also includes: means for extracting the phase α and the modulus ρ or the square of the modulus ρ from said optical signals; means for locking the length of the optical cavity; means for deriving said phase α over a given period of time in order to produce a signal comprising the overall movement information for said gyrolaser; and means for locking the activation of said gyrolaser onto said oscillatory movement, receiving said signal, extracting from which an estimation of the oscillatory movement imparted on said gyrolaser by said activation means and producing said oscillation signal whose amplitude is locked onto a given amplitude setpoint. | 10-13-2011 |
