Topic
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.
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13 Feb 1990
TL;DR: In this article, a closed-loop approach to signal processing in the fiber gyroscope is presented, in which the slope of the increasing and decreasing sections of the modulation are adjusted independently to compensate for the phase difference due to rotation rate.
Abstract: A practical closed-loop approach to signal processing in the fiber gyroscope is presented. A triangle wave phase modulation is used in which the slope of the increasing and decreasing sections of the modulation are adjusted independently to compensate for the phase difference due to rotation rate. Accordingly, the phase difference due to rotation is determined solely by the difference in the times spent on each of the legs of the triangle wave. By synchronizing these times to a clock signal, the output becomes a digital measure of rotation angle.
14 citations
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TL;DR: In this paper, the authors proposed a method to compensate for the linear acceleration effect of the thermal gyroscope by reducing the switching frequency of the heaters and the temperature sensors.
Abstract: The MEMS (micro-electro-mechanical system) thermal gyroscope uses gas instead of a solid proof mass to detect Coriolis acceleration and provides better high-shock and strong-vibration resistance than the MEMS mechanical gyroscope. Despite its mechanical robustness, the output of the MEMS thermal gyroscope is affected by linear acceleration. The MEMS thermal gyroscope described in this paper includes two symmetric heaters and two symmetric temperature sensors. By alternating power to the two heaters, a bidirectional flow of expanding gas is created. The Coriolis acceleration deflects the symmetric gas flow and produces a differential temperature between the two temperature sensors. By reducing the heaters’ switching frequency, we are able to compensate for the linear acceleration effect of the thermal gyroscope. At a low gas flow frequency, the thermal gyroscope operates in both transient and steady states. The differential temperature acquired in the transient state is a combination of the signals produced by acceleration and rotation. However, in the steady state, the velocity of gas flow produced by gas expansion and contraction drops to zero. At this point, the desired Coriolis acceleration diminishes, and the device operates solely as an accelerometer. Thus, the differential temperature signal detected in the steady state can be used to compensate for the differential temperature signal detected in the transient state. This method also provides both rotational and acceleration signals from the same device.
14 citations
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TL;DR: A He-Ne ring laser has given the Earth-rotation-induced Sagnac frequency to a precision of 1 microHz, or 2 parts in 10(8), 2 x 10(-21) of the laser frequency.
Abstract: A He–Ne ring laser has given the Earth-rotation-induced Sagnac frequency to a precision of 1 μHz, or 2 parts in 108, 2 × 10−21 of the laser frequency. Because the beat frequency in a ring laser originates in either time-reversal or (with a more complicated polarization geometry) parity-violating effects, such systems have the potential of detecting ultrasmall symmetry violations.
14 citations
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27 Jan 2006TL;DR: In this article, a resonant vibratory gyroscope is implemented using the primary flexural degenerate modes, which are used to sense rotation around the axis perpendicular to the substrate.
Abstract: Disclosed are resonant vibratory gyroscopes and fabrication methods relating thereto. The angular motion sensor comprises a resonating star gyroscope which comprises a vibratory solid or shell-type structure for rate sensing or measuring angle of rotation. The structure formed as a merged superposition of two square entities, yields in-plane degenerate flexural modes that are used to sense rotation around the axis perpendicular to the substrate. The resonating star gyroscope may be implemented using the primary flexural degenerate modes. Such an implementation has been successfully demonstrated by the authors using trench-refilled polysilicon and epitaxial polysilicon as the structural material. It is also possible to use a solid star-shaped resonator (with or without perforations) for the gyroscope. The authors also suggest the operation of the resonating star gyroscope employing the higher-order flexural modes. In this particular implementation the authors utilized a (100) single crystalline structural material.
14 citations
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10 Mar 1989
TL;DR: In this article, a ring laser gyro system with a partially transparent output mirror is described, which provides relatively undistorted circularly polarized coherent light beams to the photo detector and amplifier of the system.
Abstract: Provided herein is a ring laser gyro system having a special and improved partially transparent output mirror which provides relatively undistorted circularly polarized coherent light beams to the photo detector and amplifier of the system from the laser cavity thereof. This improved mirror achieves its results by sandwiching a non-quarterwave stack between two quarterwave stacks of multi layer, all of which are coated on a Zerodur substate mirror. The improved mirror achieves nearly Zero phase retardation and a Tp/Ts ratio equal to one.
14 citations