摇摆状态下基于非线性误差模型的惯导对准研究

Nonlinear Error Model based Alignment Method for SINS on Swing Base

摇摆状态下无法使用传统解析方法完成粗对准。为避开摇摆基座的粗对准问题,提出了基于捷联惯导非线性误差模型的直接精对准算法。推导了捷联惯导的非线性速度误差方程和姿态误差方程,基于速度量测信息给出了非线性对准模型,通过UKF算法估计失准角完成摇摆状态下的精对准。算法可允许初始姿态误差达到40°。通过计算机仿真和摇摆台试验对算法进行了验证分析。在给定试验条件下,在600秒对准时间内达到水平0.02°,方位0.17°的精度。同时计算机仿真结果表明需对惯导速度进行反馈校正来保证模型的工作精度。

Base swing causes difficulties in SINS coarse alignment. To avoid the coarse alignment, a nonlinear error model based alignment method is studied. In this method, no coarse alignment is needed, the initial attitude can be given even with an error reach 40°. Based on the nonlinear error model of SINS and the velocity measurements, a nonlinear filtering model can be made. After that the UKF is employed to estimate the misalignment angles. The nonlinear error model of SINS is deduced and non- linear filtering model is validated by the simulations and the turntable tests. Tests results show that the level attitude errors quickly decreases to 0.02°and the heading error decrease to 0.17° in the 600s alignment time. Simulation results also show that the velocity of the SINS should be feedback corrected to assurance the accuracy of alignment.