SINS大失准角传递对准模型的可观测性分析

捷联惯导系统(SINS)是在军事、航空等领域有着广泛应用的全自主导航系统,传递对准是确定其导航初值的一项关键技术.针对捷联惯导系统大失准角传递对准模型进行了可观测性分析研究.首先,建立了SINS欧拉角误差模型,并根据水平失准角为小角度的工程实际情况等对误差模型进行了简化;然后,从非线性系统的可观测性分析出发,利用微分几何理论给出系统的可观测矩阵,并给出了系统可观测度定义以及通过奇异值分解分析状态变量可观测度的方法.将该方法应用于SINS大失准角传递对准模型中,对系统进行了"速度"匹配和"速度+姿态"匹配模式下的可观测性和状态可观测度分析;最后,设计了UKF滤波器进行传递对准仿真,仿真结果与可观测分析结论一致,验证了该可观测分析方法的正确性.结果表明,这两种匹配模式下系统均为不完全可观测,并且"速度+姿态"匹配模式下状态变量的可观测度相比"速度"匹配模式下的状态可观测度高.

A novel observability analysis method for SINS large misalignment angle transfer alignment model

The strapdown inertial navigation system (SINS) is a self-service navigation system widely used in military, aviation, and other fields, and the transfer alignment is one of the key technologies of SINS. The observability analysis of SINS alignment model of large misalignment angle is studied in this paper. Firstly, the nonlinear SINS error model was deduced and the error model was simplified according to the actual engineering situation. Then, based on the observability analysis method of nonlinear theory, the system observable matrix was built using the differential geometry theory, the definition of the system observable degree and the analysis method of the state variables'' observable degree were given, and the method was applied to SINS nonlinear transfer alignment model under two different matching modes. Finally, the unscented Kalman filter (UKF) was designed for the SINS large misalignment angle transfer alignment simulation, and the simulation results verified the observability analysis.