联合旋转调制激光陀螺惯导性能在线评估

无外界基准信息时,针对舰艇单、双轴旋转调制激光陀螺航海惯导冗余配置情况下双轴旋转惯导间性能的在线评估问题,提出了联合旋转调制激光陀螺航海惯导相对性能的在线评估方法。一套单轴旋转惯导分别与待评估的双轴旋转惯导构建联合误差状态卡尔曼滤波器,状态为各系统位置误差、速度误差、姿态误差的差值及各自的陀螺漂移、加速度计零偏,以系统间的位置、速度差值为观测量,通过联合旋转调制策略编排改变系统间的相对姿态,可观性分析表明,包括单轴旋转惯导方位陀螺漂移在内的所有状态均完全可观;以不同滤波器估计得到的单轴旋转惯导方位陀螺漂移估计值的标准差为评价指标,对双轴旋转惯导随机误差进行在线评估。半实物仿真和实际实验结果表明:双轴旋转惯导激光陀螺随机误差差异的区分度可达10%;144h(6天)导航时间内,以单轴旋转惯导方位陀螺漂移估计值的标准差为评价指标,可以实现不同双轴旋转惯导相对性能的在线评估。该方法为旋转调制激光陀螺航海惯导冗余配置情况下的系统优选提供了理论依据。

Online performance evaluation of RLG INS based on joint rotation and modulation

Modern ships are usually redundantly equipped with one-axis indexing ring laser gyro (RLG) marine inertial navigation system (MINS) and several two-axis indexing RLG MINS. In order to online evaluate the relative performance of the redundant two-axis indexing RLG MINS, an online evaluation method based on joint rotation and modulation was proposed without using external benchmark information. Several joint error Kalman filters were constructed. The system states of each Kalman filter included the position error differences, the velocity error differences and the attitude error differences between the one-axis indexing RLG MINS and corresponding two-axis indexing RLG MINS, as well as the gyro drifts and horizontal accelerometer biases. With the position and velocity difference between the systems being observations, the observability analysis showed that all states including azimuth gyro drift of the one-axis indexing MINS were observable if the relative attitude between the systems was changed by the joint rotation and modulation. The azimuth gyro drift estimation standard deviation of the one-axis indexing MINS were defined as the assessment criteria to online evaluate the random errors of the two-axis indexing MINS. The semi-physical simulations and the experimental results show that the RLG random error difference of the two-axis indexing MINS can be distinguished at a level of 10% noise and the position accuracies of different two-axis indexing MINS are online evaluated according to the azimuth gyro drift standard deviation of the one-axis indexing MINS during 144 h navigation time. The proposed method provides theoretical basis for optimum system choosing in the case of one-axis and two-axis indexing RLG MINS redundant configuration.