双轴旋转式SINS自主标定技术

Self-calibration for dual-axis rotary SINS

在双轴旋转式SINS中,惯性元件常值漂移误差对系统的影响可以得到调制,但安装误差和标度因数误差对系统的影响无法得到调制,同时这些误差会与旋转角速率耦合,引起速度锯齿波等误差从而降低了系统的各项性能指标。为了减少这种影响,分析了光学陀螺双轴旋转式SINS误差传播特性,利用奇异值分解法对系统的可观测程度进行了分析,经分析,与转动轴相关的安装误差和标度因数误差的可观测度较好,据此设计了系统的自主标定方案及滤波算法,进行了数字仿真和半实物仿真验证试验。试验结果表明,利用设计的自主标定方案,在1 h内能估计出转轴上两个陀螺的标度因数误差及与转轴相关的四个安装误差,估计精度能达到95%以上。导航试验验证表明,利用自主标定的参数,相对于传统标定方法,使系统定位精度提高了20%。

In strapdown inertial navigation system, the dual-rotary modulation can completely eliminate the inertial elements constant errors of the three axes to improve the system accuracy. But the error caused by the misalignment angles and the scale factor error cannot be eliminated through dual-rotary modulation. These errors could also cause sawtooth wave velocity errors due to coupling with rotation rates. In this paper, the self-calibration of dual-axis is studied to eliminate these errors. The error models of the dual-axis rotary SINS are established, and the calibration scheme was designed based on the sixteen sequence index. Then, the PWCS observation and Kalman filter were used to analyze the observability and estimate the error factors. The results of simulation and experiments show that the designed methods are effective, and the estimation value can get 95% of the set value, the position error is reduced by 20%.