小波变换法在姿态解算中的应用

Application of wavelet transform method in attitude calculation

在惯性导航系统中,为提高陀螺仪的姿态测量精度,抑制低频噪声的影响,提出采用小波变换法融合陀螺仪、加速度计数据解算姿态角。首先将陀螺仪采集的数据进行2层小波分解,剔除低频分量和不稳定的信号,并和高频分量重构,得到滤波后的陀螺仪数据。然后利用加速度计采集的数据解算姿态角,用来不断迭代初始四元数,由初始四元数求出重力向量,再由重力向量叉积求出误差,并作PID控制来修正陀螺仪的角度。最后把修正和滤波后的陀螺仪数据用龙格库塔法计算新的四元数,用该四元数进行负增益调节,最终解算出精确的姿态角。仿真结果表明,解算姿态角的精度提高了80%,可以有效地抑制低频噪声,更加精确地计算姿态角,从而进一步提高导航系统的定位精度。

In the inertial navigation system, in order to improve the attitude measurement accuracy of the gyroscope and suppress the influence of low-frequency noise, the wavelet transform method is used to fuse the gyroscope and accelerometer data to solve the attitude angle. In this paper, the data collected by the gyroscope is firstly decomposed into two layers of wavelets to remove low-frequency components and unstable signals, and reconstructed with high-frequency components to obtain filtered gyroscope data. Then use the data collected by the accelerometer to calculate the attitude angle, which is used to continuously iterate the initial quaternion, find the gravity vector from the initial quaternion, and then find the error from the cross product of the gravity vector, and perform PID control to correct the gyroscope’s angle. Finally, the corrected and filtered gyro data are used to calculate the new quaternion using the Runge-Kutta method, and the quaternion is used to adjust the negative gain, and finally the accurate attitude angle is calculated. The simulation results show that the accuracy of calculating the attitude angle is increased by 80%,which can effectively suppress low-frequency noise and calculate the attitude angle more accurately, thereby further improving the positioning accuracy of the navigation system.