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.

Resonant waveguide laser gyro with a switched source

Abstract: Passive ring resonator laser gyro. The gyro eliminates the need for separate frequency control devices for the two counter propagating beams. A semiconductor laser diode, the source, is switched between two frequencies and its output is coupled into a branching waveguide. The light in the waveguide is coupled into a resonant ring waveguide and then sampled by detectors. The laser current is switched at a fixed rate between two values. The values are selected such as to cause the laser output to switch between the resonant frequencies of the two directions of propagation in the ring. These values are determined by a resonance tracking servo. The disclosed laser gyro eliminates the need for active frequency controlled devices in the waveguide structure resulting in less noise, better signal, and reduced cost.

Perspectives for Ring Laser Gyroscopes in Low-Frequency Seismology

Abstract: Variations in the ring laser signal of the rotating Earth are caused by local rotations and by north–south tilts. Analytic expressions for the computation of synthetic seismograms for ring lasers based on normal mode summation are derived. We find that horizontal ring lasers are predominantly sensitive to torsional motion. Synthetic Sagnac signals are computed for recent earthquakes and for spherical Earth models in order to establish the general characteristics and amplitude of the expected ring laser signals. In the normal mode band north–south tilts typically amount to less than 10% of the total signal for a horizontal ring laser. The fact that no free oscillation spectra have so far been reported from ring lasers is consistent with amplitudes of our synthetic Sagnac signals and current noise levels of these sensors.

Attitude matching method for ship deformation measurement

Abstract: A new algorithm using attitude matching method is proposed for ship deformation measurement system based on ring laser gyro units(LGUs).In the new algorithm,the Kalman filter measurements are set up based on the two LGUs' real-time attitude information which is different from the inertial measurement matching method.Each of the LGUs systems directly uses the ring laser gyros' outputs to update its attitude with respect to the inertial space,and the inertial frame is chosen to be the initial LGU frame,which can avoid the initial alignment problems and make full use of ring laser gyros' high angle measurement precision.Simulation results show that high frequency and accurate ship deformation measurement can be effectively realized,and the simulated measurement precision can be higher than 15″,which lays a sound fundation for actual application of ship deformation measurement based on LGUs.

Biassing the Raytheon Four-Frequency Ring Laser Gyroscope

Abstract: The non-reciprocal bias element necessary for operation of a four-frequency differential ring laser gyroscope (RLG) is the subject of this paper. Each of the three alternative bias approaches currently under consideration, namely, Zeeman bias, a magnetic mirror, and a Faraday cell, is discussed in the context of its effect on the performance of a RLG. Relevant results of a detailed model including cross-relaxation, Zeeman effect, hole-burning, pathlength controller operation, and temperature are given.

Single-channel phase-tracker for the open-loop fiber optic gyroscope

Abstract: A simplified analog signal processing technique for the open loop fiber optic gyroscope is described which is base on the same electronic closed-loop 'phase-shift nulling' concept reported in a previous paper . The system provides a linear output from an open ioop gyro configuration over a2ic radian range in Sagnac phase shift with good linearity and relatively low noise and drift. 1. INTRODUCTION Much of the research effort on fiber optic gyros in recent years has been directed towards thedevelopment of closed loop Sagnac phase shift detection approaches [1,2]. Typically, theseapproaches involve the use of complex, high speed electronic signal processing schemes and integrated optic components to allow a precise non-reciprocal phase shift to be introduced into theSagnac interferometer to counterbalance the rotation-induced Sagnac phase shift. These systems aregenerally aimed at high precision, low drift and wide dynamic range sensing applications, such as in- ertial navigational systems. There is, however, also considerable interest in gyros for use in less-