传统的小干扰方程并不能描述捷联惯导系统在大失准角下的误差传播特性 ,推导了姿态误差为大角度时的四元数误差方程 ,并指出当姿态误差为小量时 ,所推导的误差模型与小干扰方程是等价的。仿真结果表明在大失准角下的空中对准过程中 ,采用四元数误差方程以及非线性滤波技术能有效地提高对准精度 The traditional small perturbation equation can not describe the error propagation characteristics of SINS at large misalignment angles. The quaternion error equation is deduced when the attitude error is large. It is pointed out that when the attitude error is small, The derived error model is equivalent to the small interference equation. The simulation results show that in the process of air alignment at a large misalignment angle, the quaternion error equation and the nonlinear filtering technique can effectively improve the alignment accuracy