Ring laser gyroscope

About: Ring laser gyroscope is a research topic. Over the lifetime, 2070 publications have been published within this topic receiving 18609 citations. The topic is also known as: Sagnac interferometer.

Precise MEMS Gyroscope with Ladder Structure

Abstract: We report a precise MEMS gyroscope with a 'ladder structure', which was designed to reduce acceleration sensitivity, temperature dependence of sensitivity, and offset drift. This gyroscope has four masses linked by two parallel straight beams, and each mass oscillates in opposite directions in a driving mode. A sensor module using the fabricated gyroscope shows low acceleration sensitivity and stable characteristics in the presence of temperature changes. This gyroscope will be useful for car navigation systems, for example, where high precision is necessary.

High-precision uniaxial rotation attitude measuring system based on laser gyro

Abstract: The invention discloses a high-precision uniaxial rotation attitude measuring system based on a laser gyro, consisting of two parts including an inertia measurement unit A and a uniaxial precise machine turntable B. In the inertia measurement unit A, a laser gyro and a quartz accelerometer are fully and rigidly coupled with a bracket, the inertia measurement device A is fixed on the uniaxial precise machine turntable B by a standard fastening bolt, the relative attitude between the inertia measurement device A and the uniaxial precise machine turntable B is precisely calibrated, and the precision and the synchronism of a solving attitude of the inertia measurement device A are guaranteed. The constant drift of an inertia device in the inertia measurement unit is modulated by the periodic rotation of the uniaxial precise machine turntable, thus the alignment precision and the navigation attitude precision of the attitude measuring system are improved. The invention can provide a carrier (a ship) with real-time and complete high-precision attitude information for a long time and improve the comprehensive combat capability of the carrier.

Optically biased twin ring laser gyroscope

Abstract: An improved ring laser rotational rate sensor includes a pair of lasing cavities, each of which is comprised of a non-planar arrangement of four cavity segments. Common gain and biasing media are associated with closely-spaced segments of the two cavities. The non-planar cavity geometry supports only circularly optically polarized lasing modes thereby requiring no intracavity elements for optical biasing and eliminating the need for dithering of mirrors to control optical path length.

Ring laser gyroscope dither drive circuit

Abstract: A method and apparatus for phase locking the dither motions of a set of ring laser gyroscopes are shown. To prevent a variation of force from existing on a strapped-down sensor block having a plurality of ring laser gyroscopes means are provided permitting only one gyroscope to determine the frequency of oscillation of its dither suspension system. The remaining gyroscopes are slaved in both frequency and phase to the reference rather than acting independently, or locked in frequency only. The circuitry for the master and slave units have similar components, and operate substantially the same except that the signal from the variable frequency oscillator of the master unit is used as the second input to the phase detectors of the slave units rather than them using the output of their own variable frequency oscillators.

Stereo-camera visual odometry for outdoor areas and in dark indoor environments

Abstract: A major goal in the research and development area of navigation is to improve the accuracy and the integrity of navigational systems. Scientists and researchers in this field are working on increasing the performance of navigational algorithms while the sensors for navigation systems become smaller and cheaper. Nonetheless ring laser gyroscope (RLG) and fiber optic gyroscope (FOG) are navigational components of the high price segment. For ultra-low-cost navigation systems RLGs and FOGs are too expensive at the present time, so that predominantly MEMS IMUs (microelectromechanical system inertial measurement units) are integrated into such systems. Due to the strong drift of MEMS sensors, aiding sensors have to be used to guarantee the integrity of the system and to get a longterm stable navigation solution. To limit inertial navigation error in outdoor scenarios the usage of Global Navigation Satellite System (GNSS) is an opportunity to deal with this problem. However, it is obvious that the use of GNSS is constrained by the limited availability of satellite signals in urban canyons or indoor situations. Especially close to buildings, GNSS signals are not always available and the information of the satellite signal can be negatively impacted due to multipath and shading. This is why optical sensors like laser range finders or cameras are frequently used as aiding sensors in urban areas or inside buildings.