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.

On the Influence of Diurnal and Subdiurnal Signals in the Normal Vector on Large Ring Laser Gyroscope Observations

Abstract: The ring laser gyroscope (RLG) technique has been investigated for over 20 years as a potential complement to space geodetic techniques in measuring Earth rotation. However, RLGs are also sensitive to changes in their terrestrial orientation. Therefore in this paper, we review how the high-frequency band (i.e. signals shorter than 0.5 cycle per day) of the known phenomena causing site deformation contribute to the RLG observable, the Sagnac frequency. We study the impact of solid Earth tides, ocean tidal loading and non-tidal loading phenomena (atmospheric pressure loading and continental hydrosphere loading). Also, we evaluate the differences between available models of the phenomena and the importance of the Love numbers used in modeling the impact of solid Earth tides. Finally, we compare modeled variations in the instrument orientation with the ones observed with a tiltmeter. Our results prove that at the present accuracy of the RLG technique, solid Earth tides and ocean tidal loading effects have significant effect on RLG measurements, and continental hydrosphere loading can be actually neglected. Regarding the atmospheric loading model, its application might introduce some undesired signals. We also show that discrepancies arising from the use of different models can be neglected, and there is almost no impact arising from the use of different Love numbers. Finally, we discuss differences between data reduced with tiltmeter observations and these reduced with modeled signal, and potential causes of this discrepancies.

Elastic Dynamic Torsion of a Ring Laser Gyroscope Mechanical Dither and its Effect on the Accuracy of Attitude Determination

Abstract: We analyze the effect of the dynamic elastic torsion, which mechanical dithering devices of ring laser gyroscopes can be subject to, on the accuracy of attitude determination in a strapdown inertial navigation system. We also describe a method for calibrating their parameters in order to compensate for this effect in attitude integration algorithm. The method represents an extension of the existing technique introduced in 2009 by N.A. Parusnikov from the Moscow State University, applicable to tactical and navigation-grade inertial systems on a turntable with horizontal rotation axis. New parameters of dynamic elastic torsion get into the state vector of a linear state-space model subject to estimation. We examine their observability and predicted covariance, as well as present the experimental results.

Method for optimizing the switched-on time of a coriolis gyroscope and coriolis gyroscope suitable therefor

Abstract: A method for optimizing the switched-on time of a Coriolis gyroscope (1) having a mass system (100) which can be excited to an excitation oscillation of the Coriolis gyroscope (1) parallel to a first axis (x), wherein a deflection of the mass system on account of a Coriolis force along a second axis (y) which is provided perpendicular to the first axis (x) can be verified using an output signal from the Coriolis gyroscope, comprises determining the amplitude (A) of the excitation oscillation of the Coriolis gyroscope at a defined time, determining the output signal (S) from the Coriolis gyroscope at the defined time, and generating a normalized output signal (S0) from the Coriolis gyroscope by multiplying the determined output signal (S) by the quotient of the amplitude (A0) of the excitation oscillation of the Coriolis gyroscope in the steady state and the determined amplitude (A).

Piezoelectric drive for a ring laser gyroscope

Abstract: This paper discusses a system for adjusting the perimeter of a frequency-stabilized ring laser gyroscope. It is shown that the main error source of the gyroscope is temperature effects on the path length of the optical cavity. The design of a piezo adjuster, which is the basic element of a system for adjusting the gyroscope perimeter, is considered. The main requirements imposed on the piezo adjuster for its successful operation as part of the laser gyroscope are listed. A physicomathematical model for the piezo adjuster and a number of computer programs based on it are considered. Results are given of the numerical modelling of various designs of the piezo adjuster, including the existing design. It is shown that the output parameters of the laser gyroscope can be substantially improved by changing the geometrical parameters of the design elements.

Gyrolaser semi-conducteur à cavité externe

Abstract: A well known technique for gyrometry is to use Sagnac effect in a ring laser cavity, with a mixture of Helium and Neon as gain medium. Gyrometric qualities of this type of laser has been shown many times. But on an industrial point of view, the fact that the gain medium is a gas is the source of the limitations of the system. Other solutions based on Nd :YAG cristal have shown that it is possible to get a Sagnac signal in other kind of gain medium. However, the quality of the frequency response is limited by the long fluorescence time (230 μs) of this gain medium. Semi-conductor gain medium, through its much shorter luminescence time (3 ns) offers great opportunity of gyrometry. The possibility of electrical pumping could also give a string cost reduction. The goal in this thesis is to study the possibility of a ring laser gyroscope based on a semi-conductor gain medium in a free space cavity. The gain medium dynamic is strongly different from previously quote gain media. First we will have to study stability conditions of gyrometric behavior of such a system, and also gyrometric performance one can expect. Influence of phase-amplitude coupling, specific to semiconductor, will be shown. Second, experiment shows that we have been able to get a gyrometric behavior in ring cavity with a 1/2-VCSEL thanks to a suitable laser cavity geometry and a feed back loop to control laser intensities in order to counteract mode competition which take place in semiconductor gain medium.