基于变步长LMS算法的IMU信号降噪研究

针对遥测系统小型化惯性测量单元惯性敏感元件精度较低,随机噪声较大的情况,研究基于变步长LMS自适应滤波技术的IMU信号实时降噪问题。算法通过实时递推得到失调误差和输入信号的互相关系数估值,利用估值实现算法的变步长控制,克服了固定步长NLMS滤波在收敛速度、跟踪能力和稳态精度之间的矛盾,具有收敛速度快、稳态精度高、动态信号随机噪声抑制能力强的优点。实验表明,变步长LMS自适应滤波技术可有效降低IMU信号的随机噪声,为遥测系统测量精度的提高提供技术支撑。

Noise attenuation of IMU signal based on variable step size LMS algorithm

To reduce the random noise of inertial sensors with low precision in IMU of telemetry system,a variable step-size LMS(VSSLMS)adaptive filter is applied to noise attenuation of IMU signal.An estimated cross-correlation coefficient between the offset error and the input signal is used to control the step size of the algorithm.Then the contradiction among the convergence speed,tracking performance and steady-state accuracy of the fixed step-size NLMS is overcome.Compared with the fixed step-size NLMS algorithm,the faster convergence speed,higher steady-state accuracy and better noise attenuation of dynamic signal can be achieved.It has been shown by experiments that the random noise of slave IMU signal is effectively reduced with the use of VSSLMS adaptive filter,which can offer a technical support for the improvement of measurement precision of telemetry system.