针对旋转式捷联惯导中惯性测量单元(IMU)旋转角速度变化过程(以加减速过程为主)对系统定位精度的影响进行分析和研究。建立了基于地理坐标系下的角变速过程的运动模型,并以此为基础推导了旋转运动抵消等效陀螺漂移误差的基本原理。结合在工程中普遍使用的单轴四位置八次序转停方案,详细分析了IMU加减速过程对捷联惯导系统定位精度的影响。在理论分析的基础上利用仿真试验比较了不同加减速旋转方案的定位误差,仿真结果验证了角变速运动能够显著影响旋转式捷联惯导系统的定位精度。
The influence of inertial measurement unit (IMU) rotary angular velocity variation on positioning accuracy of strapdown inertial navigation system (SINS) was studied. Angle variable motion model was established in geographic coordinate system. Then, the basic principles that equivalent gyro drift errors were compensated by rotary motion were derived. Combined with the widespread single-axis 4-position and 8-order rotation-stop scheme, the effect of acceleration and deceleration of IMU on positioning accuracy of SINS was analyzed in detail. Simulations based on theoretical analysis were carried out. Finally, the positioning errors of rotation schemes with different acceleration and deceleration were compared by simulation tests, the results verified that the accuracy of the rotary SINS was apparently impacted by angle variable motion.