基于线性相位无限长单位冲击响应滤波器的机抖激光陀螺POS低时延降噪方法

Low time delay de-noising method for mechanically dithered RLG POS based on linear phase infinite impulse response filter

针对传统线性相位有限长单位冲击响应滤波器在机抖激光陀螺位置姿态测量系统(Position andOrientation System,POS)降噪解调中存在着运算量大和时延大的问题,提出一种基于线性相位无限长单位冲击响应滤波器的降噪解调方法。在时域内通过卡尔曼滤波参数估计使无限长单位冲击响应低通滤波器逼近线性相位有限长单位冲击响应低通滤波器,获得线性相位;在频域内建立无限长单位冲击响应低通滤波器目标函数,采用拟牛顿法对其进行优化求解,以降低其时延;再设计低阶线性相位无限长单位冲击响应带阻滤波器,降低滤波器运算量。实验结果表明,与传统的有限长单位冲击响应低通滤波方法相比,采用该方法设计的线性相位无限长单位冲击响应滤波器进行机抖激光陀螺POS降噪解调,在保证降噪解调效果的情况下,运算量减少超过40%,时延平均从10.125 ms减小到4.83 ms。

The traditional linear phase Finite Impulse Response（FIR） filter had the disadvantages of large computation complexity and long time delay in mechanically dithered Ring Laser Gyro（RLG） Position and Orientation System（POS） noise attenuation.In this paper,a noise attenuation method based on linear phase Infinite Impulse Response（IIR） filter was proposed.In time-domain,a linear phase IIR lowpass filter was obtained by approaching a linear phase FIR lowpass filter through Kalman filter parameter estimating.In frequency-domain,the target function of the IIR lowpass filter was established and it was optimized by Quasi-Newton method.The time delay of the IIR filter was decreased.To further reduce computation complexity,a new low order IIR bandstop filter was designed.The experimental results show that the linear phase IIR filter designed by this method decreases the computation complexity by more than 40% and reduces the time delay from 10.125 ms to 4.83 ms with guaranteeing the noise attenuation performance,compared with the traditional FIR lowpass filter.