壳体翻滚是提高空间稳定系统长时间工作精度的技术手段之一，但其失准角误差将引起速度和姿态扰动。对该误差进行建模、标定与补偿是解决此问题的有效措施。在误差补偿时，由冗余角变化导致的交叉耦合影响对长航时高精度惯导系统是不能忽视的。根据壳体翻滚失准角误差矢量的几何投影关系，建立物理平台坐标系（P系）与陀螺三面体坐标系（G 系）之间的坐标转换关系，分析冗余角变化引入的交叉耦合影响，并进行计算机仿真和实际试验。结果表明：冗余角使P系相对G系沿z向的角运动附加极轴壳体翻滚周期分量，其幅值为失准角与冗余角正切函数的乘积；误差补偿考虑这一项，东速、横摇和航向精度十天可提高30%~50%。%While Case rolling is one of the techniques for improving long term accuracy of space-stable systems, its non-alignment errors would cause velocity and attitude disturbances. Modeling, calibrating and compensating the non-alignments is an effective solution. Cross coupling effect due to redundancy angle variation should be considered in compensating high-accuracy long-time inertial navigation systems. In this paper, the coordinate transformation between physical platform frame (P frame) and tri-axial gyroscope frame (G frame) is established based on the geometric projection of case rolling non-alignment angle error vectors, and the cross coupling effect is analyzed. Simulation and test results show that, due to redundancy angle, there exist periodic components of polar case rolling in z-axis angular motion of P frame with respect to G frame, whose amplitude equals the product of non-alignment angle and tangent of redundancy angle. The errors of east velocity, roll and yaw can be reduced by 30%-50% in ten days with the proposed error compensation model.
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