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.

Path length controller for ring laser gyroscope

Abstract: A ring laser gyro path length controller has a cup-like fixture which mounts a piezoelectric actuator and is bonded directly to the gyro block. A mirror assembly is concentrically located within the fixture and is independently mounted to the gyro block thereby enabling independent assembly and disassembly of the fixture and the assembly. Diaphragm sections of the assembly are coaxially positioned and connected to a diaphragm section of the fixture so that bidirectional displacement of the assembly may occur and the moment generated by the actuator results in an axial deflection force on the assembly. A strip of material having a high coefficient of expansion is mounted to the piezoelectric actuator to augment the deflection force as temperature increases thereby reducing the power demands of the actuator.

Research on Parameter Estimation Methods for Alpha Stable Noise in a Laser Gyroscope’s Random Error

Abstract: Alpha stable noise, determined by four parameters, has been found in the random error of a laser gyroscope. Accurate estimation of the four parameters is the key process for analyzing the properties of alpha stable noise. Three widely used estimation methods—quantile, empirical characteristic function (ECF) and logarithmic moment method—are analyzed in contrast with Monte Carlo simulation in this paper. The estimation accuracy and the application conditions of all methods, as well as the causes of poor estimation accuracy, are illustrated. Finally, the highest precision method, ECF, is applied to 27 groups of experimental data to estimate the parameters of alpha stable noise in a laser gyroscope’s random error. The cumulative probability density curve of the experimental data fitted by an alpha stable distribution is better than that by a Gaussian distribution, which verifies the existence of alpha stable noise in a laser gyroscope’s random error.

Re-Entrant Fiberoptic Approach To Rotation Sensing

Abstract: We are investigating a new approach to inertial rotation sensing which we refer to as an active re-entrant Sagnac system (ARS). It is aimed at rotation rates extending to very low values, as required in such amplications as navigation, guidance and geophysical measurements. It employs a multiturn fiber optic loop containing an internal optical amplifier, and uses pulsed optical signals introduced by an external laser oscillator which make multiple recirculations around the loop. Its output signal is a time-sampled sinusoidal waveform having the same frequency as the beat frequency in a standard oscillating ring laser gyro (RLG) having the same loop diameter. Like the RLG, it is basically an integrating rate gyro, in which digital cycle counting is used to determine the angle turned through. It is basically free of the mode locking effect encountered with RLG's, and has prospect for higher sensitivity to rotation. Experiments using cw light are described, which include new re-sults on removing instabilities and environmental sensitivities from fiber gyros. Initial experiments on pulsed recirculation without an amplifier are described, which affirm the basic recirculation principle. Work is beginning on development of a fiber amplifier for use in a full ARS experiment.

Apparatus and method for the elimination of angular vibration induced errors in ring laser gyroscopes

Abstract: In a ring laser gyroscope which has a triangular block configuration, and which incorporates a triangular shaped laser resonant cavity defined by three corner mirrors, including an output mirror, the gyroscope is sinusoidally dithered to reduce lock-in effects at low angular rotational rates and the gyroscope output is corrected for error caused by lock-in at the extremities of each oscillation when the dither velocity is equal to zero by accumulating the ac voltage outputs of a photodiode measuring the light intensity of the interference pattern at each zero dither velocity and when the accumulated phase error reaches 2π an overflow or borrow pulse is generated and added to the normal gyroscope output thereby correcting for the accumulated errors caused by lock-in at zero dither velocity.