捷联惯导加速度计尺寸效应误差建模及其标定

Modeling and Calibration of the Accelerometer Size Effect Error of the SINS

高动态条件下,加速度计(简称加计)的尺寸效应将成为捷联惯导系统精确导航的重要误差源。这个误差源于加计组合中三个加计振动中心(有效的加速度测量点)的不重合。从几何角度对加计尺寸效应误差进行了建模。设计了三类基于精密三轴速率转台的加计尺寸标定方案,即匀角速度旋转、匀角加速度旋转和正弦角加速度旋转方案。以旋转过程中捷联惯导系统的速度输出作为量测,利用Kalman滤波器可以实现对加计尺寸系数的有效估计。利用分段定常系统可观性分析方法研究表明,三类旋转标定机动均能使系统状态完全可观测。仿真结果证明了三类标定方案的有效性,而以匀角速度旋转方案估计过程最平稳,以正弦角加速度旋转方案估计精度最高。

In high angular dynamic environments,accelerometer size effect,which is due to the fact that the center of seismic mass（the effective acceleration measurement point） of each accelerometer in the triad could not be physically collocated,becomes a dominant error source for accurate navigation of a Strapdown Inertial Navigation System（SINS）.A size effect error model is deduced from a geometric viewpoint.Three kinds of calibration scheme based on a precise triad-axis rate turntable are devised,namely the constant angular rate rotation,the constant angular acceleration one and the sine angular acceleration one.A Kalman filter for processing the velocity measurements of the SINS during rotation is formulated to estimate the size effect coefficients.Through the observability analysis of piece-wise constant system（PWCS）,the error model under three different calibration motions are all completely observable.The simulation results validate all the calibration schemes＇ feasibility and indicate that the first motion results in the most smooth estimate process while the third one promises the best estimation accuracy.