惯导平台自标定中安装误差可观性分析  

Observability analysis of IMU's misalignment angles in self-calibration for inertial platform

作　　者：许永飞[1] 张士峰[1] 

机构地区：[1]国防科学技术大学航天科学与工程学院,长沙410073

出　　处：《中国惯性技术学报》2015年第5期575-579,584,共6页Journal of Chinese Inertial Technology

基　　金：航天科技创新基金(CASC201105)

摘　　要：针对惯导平台连续翻滚自标定中安装误差标定精度不高这一现状,提出了一种解决方案。通过对惯性器件的输出误差模型和安装误差的分析,建立了系统的姿态动力学方程和观测方程,利用输出灵敏度理论分析了系统的可观性,指出加速度计安装误差可观性较差是影响标定精度的主要原因。利用Kalman滤波中的估值方差矩阵计算了安装误差之间的相关系数,计算结果表明可观性差是由安装误差之间的线性相关性造成的,并确定了具体的不可观参数。以加速度计输入轴为基准建立平台坐标系可以减少安装误差项,使所有的安装误差的变得可观。最后的仿真结果表明在新的方案下,安装误差的估值偏差小于5",标定精度得到了显著提高。An improved scheme for inertial platform is proposed to solve the problem that the calibration accuracy for the misalignment angles is not high in the continuous rotation self-calibration. Combining with the output error model and misalignment angles of the inertial device,an attitude dynamic model and observation equations are established. The system＇s observability is analyzed based on the theory of output sensitivity. According to the analysis,it is the low observability of the accelerometers＇ misalignment angles that mainly affects the calibration accuracy. Correlation coefficients are calculated with the estimation error covariance matrix in the Kalman filter,and the calculation results indicate that the low observability is caused by the linear correlations. A new scheme is proposed by establishing the platform coordinate system based on the input axis of one accelerometer,which can reduce the number of the misalignment angles and make all the error parameters observable. Simulation results show that the estimation error of the misalignment angles is less than 5＂ and the calibration accuracy is significantly improved by the improved scheme.

关 键 词：惯导平台 安装误差 可观性 输出灵敏度 相关系数 

分 类 号：V441[航空宇航科学与技术—飞行器设计]