激光捷联惯组(LSIMU)在工作环境下受测量噪声干扰大,尤其是小型激光陀螺仪,不能精确识别地球自转角速度,导致捷联惯导系统无法准确、快速对动基座进行初始对准。针对该问题,提出了一种基于小波卡尔曼级联滤波的LSIMU动基座初始对准算法。仿真对比实验结果表明,相比其他初始对准算法,本算法可以有效提高初始对准精度、减小姿态角对准误差,将全球定位系统辅助激光捷联惯导系统的初始对准精度从10''提高到了5''以内,且方差最小,可以使对准误差更稳定、快速的收敛。

Contrary to expectations, a measurement of the random walk in the ring laser gyro (RLG) as a function of laser power P shows that it is not consistent with the P^{-1/2} rule. In the experiment, the random walk and laser power are tested and recorded at different discharge currents. The random walk decreases with increasing power, but with a rate much less than the theoretical value according to current literature. In order to solve the inconsistency above, we derive the expression for the random walk in RLGs based on laser theory. Theoretical analysis shows that, accumulating effects of lower energy level due to its limited lifetime lead to additional quantum noise from spontaneous emission. Results show that the random walk in the RLGs consists of two components. The former decreases with increasing power according to the P^{-1/2} rule, whereas the other is power-independent. Thus far, the power-independent quantum limit has not appeared in the literature; therefore, the expressions for RLGs should be modified to describe the low-loss RLGs exactly, where the power-independent term takes a relatively larger proportion. The findings are significant to the further reduction of quantum limit in low-loss RLGs.

In ring laser gyros (RLGs), dynamic lock-in, which results from information loss in the lock-in region, occurs when a constant sine bias is introduced. However, sampling some signals in the lock-in region for a particular duration allows the retrieval of lost information. It is demonstrated how dynamic lock-in and the flat region in the input-output curve near the zero angle rate can be eliminated after compensation.

Lock-in phenomenon in ring laser gyroscopes is directly related to effective backscattering, which includes both backscattering and nonuniform loss. Effective backscattering often differs in different states and can only be reflected in a working state via online estimation in the working state. Moreover, effective backscattering can result in the intensity modulation of beams in the opposite directions. The effective backscattering parameters can be obtained by measuring the weak modulations in the intensity signals under different rotation rates and by using the curve-fitting method. This letter demonstrates the online estimation of backscattering.

Bias of ring-laser-gyroscope (RLG) changes with temperature in a nonlinear way. This is an important restraining factor for improving the accuracy of RLG. Considering the limitations of least-squares regression and neural network, we propose a new method of temperature compensation of RLG bias-building function regression model using least-squares support vector machine (LS-SVM). Static and dynamic temperature experiments of RLG bias are carried out to validate the effectiveness of the proposed method. Moreover, the traditional least-squares regression method is compared with the LS-SVM-based method. The results show the maximum error of RLG bias drops by almost two orders of magnitude after static temperature compensation, while bias stability of RLG improves by one order of magnitude after dynamic temperature compensation. Thus, the proposed method reduces the influence of temperature variation on the bias of the RLG effectively and improves the accuracy of the gyro scope considerably.

Several results on optical-axis perturbation and elimination of the mismatching error C of a monolithic triaxial ring resonator (MTRR) are reported. Based on the augmented 5￡5 ray matrix method, by simultaneously considering axial displacement of a mirror and the misalignments in three planar square ring resonators of a MTRR, the rules of optical-axis perturbation are obtained. The mismatching error C of the MTRR is eliminated. The results obtained are important for cavity design, as well as in the improvement and alignment of MTRR.

A direction related polarizer was inserted into a ring laser cavity to eliminate one of the two eigen-modes as well as spatial hole burning of the gain medium in a bidirectional Er-doped fiber ring laser. Thus, a fiber ring laser gyroscope (FRLG) operating in continuous wave was demonstrated. A beat signal of over 30-dB noise was observed and a good linear relation between the beat frequency shift and cavity rotation rate was obtained.

Scale factor of a constant rate biased ring laser gyro (RLG) is studied both theoretically and experimentally. By analyzing experimental data, we find that there are three main terms contributing to the scale factor deviation. One of them is independent of time, the second varies linearly with time and the third varies exponentially with time. Theoretical analyses show that the first term is caused by experimental setup, the second and the third are caused by un-uniform thermal expension and cavity loss variation of the RLG.

Thermal effects impose the greatest limit on the precision of a ring laser gyro (RLG). Selections of temperature sensing points were comparatively discussed based on large numbers of experimental data to improve its precision, and the optimum combination was selected to establish a practical compensating model. The model is applied to new experimental data under the given and varied temperatures. Results show that the bias trend changing with the temperature is basically eliminated and the bias stability is enhanced significantly.