摘要
针对现有低成本微机械惯性器件无法满足宽带移动卫星通信系统在机动状态下天线指向精度的问题,提出了微机械惯性测量单元与闭环跟踪信息相结合的姿态确定算法.该算法在航向上引入闭环跟踪的指向偏差角,经PI控制器反向校正航向陀螺的漂移误差,并利用跟踪指向信息的低频分量和陀螺的高频分量估计航向角.在横滚和俯仰上,首先以改进欧拉角作为状态向量,根据陀螺角速率信息和加速度计的重力场信息分别建立状态方程和测量方程;然后依据航向角速率和俯仰角偏差对载体运动状态进行判别,并在载体机动下调整方差矩阵以依赖陀螺进行姿态估计,克服机动加速度的扰动.实验结果表明,该算法与自适应卡尔曼滤波器相比,在载体机动状态下精度更高,其航向估计精度在±0.8°,倾角在±0.5°内,满足动中通姿态稳定精度要求.
A hybrid attitude determination method that combines MEMS inertial measurement unit and close-loop tracking information is proposed for broadband mobile satellite communication to solve the problem that the existing low cost MEMS inertial sensors are hard to meet the pointing requirements during the vehicle maneuver. A heading pointing error deduced by tracking is used to correct the drift of the heading gyro by a proportional-integral （PI） controller, and the heading angle is estimated as the sum of the high pass filtered gyro output and the low pass filtered tracking heading output. Modified Euler angles are used as state variables, and the state equation and measurement equation are respectively built from the angular output of gyros and the gravity output of accelerometers. The filter recognizes the situation of dynamic condition with heading angular rate and pitch error to make the filter more robust regarding acceleration disturbances, and modifies the measurement covariance matrix to estimate the tilt based on gyros under varying vehicle dynamics. Experimental results show that the proposed method has a higher pre- cision than the conventional AKF method in dynamic mode, and the errors are less than 0. 8 degree in heading and 0. 5 degree in tilt, which is feasible for attitude stabilization of broadband mobile satellite communication.
出处
《西安交通大学学报》
EI
CAS
CSCD
北大核心
2011年第6期64-68,共5页
Journal of Xi'an Jiaotong University
基金
国家高技术研究发展计划资助项目(2010AA7010213)
关键词
卫星通信系统
姿态确定
传感器融合
改进欧拉角
satellite communication system
attitude determination
sensor data fusion
modified Euler angles
