Showing papers on "Ring laser gyroscope published in 1973"

Vibrating ring gyro

Abstract: An extremely simple gyroscope for use in a strapdown system having a vibrating ring as the gyroscopic element. The ring is supported and vibrated by an electrostatic field, established by a voltage supplied to case-fixed electrodes. An additional pair of fixed electrodes senses the position of the nodes of vibration of the ring and an eddy current drive forces rotation of the ring to move the nodes back to a reference position. Optical sensing means provide the pick-off, sensing the direction and amount of rotation required to move the ring back to the nodal reference position.

High performance ring laser gyroscope with magneto-optical bias

Abstract: A ring laser gyroscope capable of producing an output signal at low rates of angular rotation. A differential magneto-optical bias system eliminates the requirement of extreme stability in the bias system.

Sequentially switched laser gyro

Abstract: A laser gyro having a polarization anisotropy in the optical path includes means for adjusting the physical length of the closed loop laser cavity, for adjusting the isotropic resonant frequency of the cavity, cyclically, thereby to cyclically alternate the sustained laser oscillations between two essentially orthogonal polarization states at wavelengths which are adjusted upwardly or downwardly from the isotropic cavity resonant wavelength so that the wavelength of each sustained wave will be essentially at the maximum of the gain versus wavelength profile of the laser gain medium. Additionally, bias used to avoid frequency locking is sequentially reversed. Rate indications resulting from operation with one polarization are subtracted from indications resulting from operation at the other polarization, which yields double the sensitivity obtained with bias switching alone and provides cancellation of magnetic field effects and bias irregularities, as well as adverse effects, such as those due to backscattering. Opposite circular, elliptical, or linear polarizations may be used. The disclosure includes a variety of modes for sequential operation and for non-sequential differential operation.

Periodic faraday bias and lock-in phenomena in a laser gyro.

Abstract: A simple theoretical description of coupling phenomena in a laser gyro has been developed. In particular, this allows the calculation of the residual nonlinearity of the response of the laser gyro in the presence of a periodic bias. A laser gyro has been constructed in a CER-VIT block. To solve the lock-in zone problem this detector contains a periodic bias system using the Faraday effect. The results of a number of trials are reported. In particular, we obtain experimental values of residual error due to coupling phenomena for each rotational speed. These results are in good agreement with a simple coupled-oscillators theory.

RF Cleaning - Ring Laser Gyro

Abstract: : One of the most significant problems confronting ring laser development is short life. The key to long ring laser life is a clean cavity (free of contaminants). The objectives of the contract were to test the RF cleaning concept and to build deliverable RLG hardware including both sensors and electronics. The RF cleaning study was performed to determine the feasibility of using RF energy to clean ring laser gyro cavities. A 'dual discharge' approach was selected as the most suitable RF coupling technique for cavity cleaning. Experimental studies were conducted to select and optimize cleaning parameters and procedures. Comparative effectiveness of cleaning techniques was measured by optical spectroscopy and by life test of operational ring laser instruments. Data are presented which indicate that oxygen is the most efficient cleaning gas and that RF cleaning used in conjunction with normal thermal degassing processes can provide for improved laser gyro cleanliness. Conclusions and recommendations for future studies are also presented. Instrument and electronic design of the deliverable hardware are described. Autonetics state-of-the-art design and processing techniques are incorporated in the sensor design. Operating procedures and test results obtained with the equipment at Autonetics are given. A summary is presented of brief studies conducted on RLG reliability, maintainability, and system safety.

Ring laser gyroscope

Abstract: A single-mode laser gyroscope having two oppositely directed laser beams is provided at the three or four reflection points with mirrors which can be mechanically vibrated Each mirror is mounted in such a manner that it can be moved due to the expansion and contraction of stacks of piezoelectric elements which are allocated to each mirror The mirrors are vibrated or oscillated with the same frequency and phase relationship to one another towards the outside and inside so that the circumferential distance for the laser cavity is kept within a fixed number of wavelengths but the laser beam is moved backward and forward over the surfaces of the mirrors Due to this technique, the unwanted phenomenon of synchronisation at low rotational speeds is avoided without special optical or magnetic arrangements being required in the path of the laser beam