机抖激光陀螺IMU信号低时延滤波技术研究

Research on Technology of Dithered RLG IMU Signal Filter with Short Delay Time

在小型无人直升机领域,激光陀螺捷联惯导不仅用于导航,而且用于飞行姿态控制,对激光陀螺捷联惯导的导航精度和实时性都有较高要求。而传统的高阶有限脉冲响应(FIR)低通滤波器对激光陀螺惯性测量单元(IMU)输出信号滤波后会产生较大的时间延迟,使得滤波后信号难以满足系统姿态控制的要求。为了兼顾测量精度和响应时间,研究了一种最小均方(LMS)自适应陷波器与低阶FIR低通滤波器相结合的滤波方法,并在其中引入了无限脉冲响应(IIR)窄带滤波器,解决了抖频参考信号的获取问题。理论分析和试验结果表明:该方法不仅能有效消除抖动偏频信号和外界高频噪声的影响,而且可以显著缩短延迟时间至2 ms,具有很高的工程实用价值。

In the field of small unmanned helicopter,strapdown inertial navigation system(SINS)of laser gyro is not only used for navigation,but also used for flight attitude control. The requirement of navigation accuracy and real-time capability of laser gyro SINS is higher. But the traditional high-order FIR low pass filter to laser gyro IMU signals has a large time delay,so that the filter is difficult to satisfy the system. In order to take care of the measurement accuracy and response time,a filter method that combined LMS adaptive notch filter and low-order FIR low pass filter is studied,and the IIR narrowband filter is introduced in order to solve the acquisition problem of the dither frequency reference signal. Theoretical analysis and test results show that the method can not only effectively eliminate the impact of the dither offset frequency signal and the outside world high frequency noise,but also can significantly reduce delay time to 2 ms. It has very high engineering practical value.