基于AEKF的地磁/陀螺姿态解算融合算法

AEKF-based Fusion Algorithm for Geomagnetic/gyroscope Attitude Solving

摘要:

针对磁传感器在一定特殊环境下可能出现俯仰角“二值性”问题,导致无法正确判断其俯仰角变化方向,提出了一种基于地磁/陀螺信息的自适应扩展卡尔曼滤波(AEKF)数据融合算法,在分析弹体短期机动姿态运动特性的基础上,利用地磁信息无时间累计误差和MEMS陀螺短时精度高的优势,建立了卡尔曼状态系统方程和非线性量测方程,实现了姿态角的实时修正和参数的自适应更新。通过仿真和半物理试验分析验证了该融合算法的有效性,试验结果表明,该算法消除了单历元地磁解算姿态角出现的“二值性”问题和传统卡尔曼滤波发散的问题,显著提高了滚转角和俯仰角的解算精度,解算精度误差可保持在±1°以内。该算法有效减小了磁场干扰对精度解算带来的影响,在旋转弹药的姿态角测量及导航领域具有广泛的应用前景。

Abstract:

Aiming at the problem of pitch angle "duality" that may occur in magnetic sensors under certain special environments, which makes it impossible to correctly judge the direction of its pitch angle change, this paper proposes an adaptive extended Kalman filter (AEKF) data fusion algorithm based on geomagnetic/gyroscopic information, and based on analyzing the characteristics of short-term maneuvering attitude of a projectile, the system equation of Kalman state and nonlinear measurement equations are established. Based on the analysis of the short-term maneuvering attitude and motion characteristics of the projectile, the Kalman state system equations and nonlinear measurement equations are established by taking advantage of the geomagnetic information with no time accumulation error and the MEMS gyro with high short-term accuracy, and realizing the real-time correction of the attitude angle and adaptive updating of the parameters. The effectiveness of the fusion algorithm is verified through simulation and semi-physical test analysis, and the test results show that the algorithm eliminates the "duality" problem of single-calendar-element geomagnetic solving of the attitude angle and the dispersion problem of traditional Kalman filtering, and significantly improves the solving accuracy of the roll angle and the pitch angle, and the solving accuracy error can be kept within ±1°. The algorithm effectively reduces the influence of magnetic field interference on the accuracy of the solution, and has a wide range of application prospects in the field of attitude angle measurement and navigation of rotating munitions.