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.

Evaluation and Suppression of the Effect of Laser Frequency Noise on Resonant Fiber Optic Gyroscope

Abstract: This article provides a novel method to analyze and calculate the effect of laser frequency noise on a resonant fiber optic gyroscope (RFOG). The output signal of the fiber ring resonator is expressed as the sum of various harmonic responses. It is found that the laser frequency noise at certain noise frequency would be demodulated together with the rotation-induced frequency signal, and thus deteriorating the gyro output stability. A theoretical model is then setup. The effect of laser frequency noise on the RFOG based on the separate modulation-demodulation technique is numerically evaluated and the effectiveness of the reciprocal modulation-demodulation technique is verified both theoretically and experimentally. The measured angular random walk of the reciprocal RFOG improves as the detected light power at the photodetector increases, which indicates that the measured angular random walk reaches the theoretical shot-noise limited sensitivity in the RFOG. The best value is 0.0021 °/√h when the light power arrived at the photodetector is 69 μW.

Random dither modulation of a ring-laser gyroscope

Abstract: In this paper we discuss the possibilities to circumvent the lock-in nonlinearities in a dithered ring-laser gyroscope by random modulation. We review the Cayley matrix formulation of the theory of a dithered ring laser and show that it is particularly suitable to give both an intuitive understanding and a quantitative calculational tool for the effects of randomness on the gyroscope performance. The relationship of our problem to the related physical problems of an overdamped Josephson junction and a random atomic chain is pointed out. The Saxon–Hutner result is utilized to suggest a method to circumvent all locking and trapping phenomena in the laser gyroscope. The effects of amplitude or frequency noise are discussed, but it is found that the introduction of a randomly varying phase is most efficient in eliminating phase trapping. This can be used to provide an even distribution of the Cayley-mapping fixed points around the unit circle that provides the most even phase motion possible. The response of the gyroscope is then found to be optimally linear. All numerical calculations reported are based on the analytically solvable square-wave dither case, but, using the intuitive picture of the process provided by the Cayley transformation method, we argue that the results are qualitatively valid also in the case of a phase-modulated sinusoidal dither signal. The work is related to earlier work on ring lasers and Josephson junctions.

Ring laser gyroscope

Abstract: The gyroscope includes a device for producing two counter-rotating beams of laser radiation around a closed path defined by at least three mirrors. A first one of the mirrors is partially transmissive of the radiation in each beam. A detector is responsive to the laser radiation passing through the first mirror to derive electrical signals dependent upon the rotational forces acting upon the gyroscopes about a predetermined axis. A second one of the mirrors is totally reflecting and is associated with transducer operable to vary continuously the position of the second mirror. A second detector is responsive to laser radiation in each of the beams to derive alternating current signals to control the transducer. A control device is responsive to the direct current component of the output of the second r detector to maintain the intensity of the laser beams at a constant value.

Acceleration sensing ring laser gyroscope

Abstract: A ring laser gyroscope functions both as a standard gyroscope and as an accelerometer. As the ring laser gyroscope experiences acceleration along its input axis, the frame bends and position sensing photodiodes are utilized to detect the optic axis motion and laser beam intensity. By measuring optic axis shifts along the gyro input axis during acceleration, a signal proportional to acceleration is obtained.

Laser gyro position and orientation system time synchronization method

Abstract: Provided is a laser gyro position and orientation system (POS) time synchronization method The invention relates to a method for synchronizing the time of an inertial measurement unit (IMU) and the time of a POS computer system (PCS) in a laser gyro POS to the time of a global navigation satellite system (GNSS) The time synchronization method comprises the following steps: first, determining the rated correction time for time synchronization according to the precision of a laser gyroscope and an accelerometer; then, calibrating the actual working frequencies of the clock sources of the IMU and the PCS according to the pulse per second (PPS) of GNSS; and finally, synchronizing the time of IMU to the time of GNSS by gradually adjusting the sampling period of IMU, and synchronizing the time of PCS to the time of GNSS by aligning the timing start time of PCS to the PPS The time synchronization problem of the laser gyro POS and GNSS is solved, and the time synchronization precision and stability of the laser gyro POS are significantly improved