机械抖动激光陀螺新型信号处理方法的研究

Research on new signal processing method of mechanically dithered ring laser gyro

针对高速采样低通滤波的线性脉冲响应(FIR)滤波器在机械抖动激光陀螺(MDRLG)信号处理中存在着较大的时延,限制MDRLG在快速跟踪中的应用,基于相关滤波技术提出了一种新的信号处理方法。对这一方法的基本理论进行了分析,并基于Labview实现了仿真。相关滤波后,激光陀螺输出中的抖动信号衰减了约41dB,还不能达到激光陀螺应用的要求,可以适当加一低阶的FIR低通滤波器去除抖动剥除后剩余的抖动成分和高频噪声。在静态条件下用这三种信号处理方法分别对激光陀螺零偏进行了测试。相关滤波法所测得零偏稳定性(1σ00)比50阶FIR滤波器差了将近三倍,相关滤波后再经过22阶的FIR低通滤波测得的零偏稳定性比50阶FIR低通滤波器的测试结果大了不足0.001°/h,延迟时间却从4.9ms减小至2.1ms。

The common method to remove the dither signal of the Mechanically Dithered Ring Laser Gyro（MDRLG） at present is to design a Finite Impulse Response（FIR） low pass digital filter.The order and the delay time of the FIR filter will be much high to achieve well performance,which limits the use of the MDRLG in fast tracking inertial navigation system（LINS）.A new signal processing method based on correlate filter is proposed.The basic theory is analyzed.The simulation is realized based on Labview.Tests show that dither signal can be attenuated 41dB by this method.The residual dither signal and high frequency noise can be removed by 22-order low pass filter.In room temperature and static state,null drift stability tests are performed.The test results indicate that a hundred second root-mean-square（σ100） of measured null drift value tested with dither stripper is three times of that tested with 50-order FIR low pass filter.The σ100 tested with dither stripper plus 22-order FIR low-pass filter is only 0.001°/h larger than that of 50-order FIR low pass filter,but the delay time can be reduced from 4.9ms to 2.1ms.