Research On Data Processing Of Maglev Gyroscope Based On Frequency Domain Analysis And Multivariate Filtering

With the development of underground engineering,the precision of tunnel penetration is required to be higher and higher.The high precision maglev gyro total station broke through the support mode of the traditional suspended gyro,and adopted the maglev support system and torque feedback technology to realize the automatic determination of true north azimuth.As a highly sensitive instrument,the rotor current data collected by the maglev gyro total station are easily affected by the external environment.How to remove the noise in the data and improve the observation accuracy has become the focus of this paper.The main content of this paper is the time-spectrum analysis of rotor current and multivariate filtering.Firstly,carry out Hilbert transform(HT)on the rotor current data to draw the timefrequency amplitude spectrum of the signal,analyze the signal from two aspects of time domain and frequency domain,judge the noise type in the signal and its relationship with the external environment,and roughly divide it into six types according to the characteristics of the signal,so as to prepare for the subsequent filtering processing.Then wavelet transform(WT)and Hilbert-Huang transform(HHT)are used to process the signal.For wavelet transform to adopt four kinds of evaluation index to determine the optimal decomposition filter series,a novel Hilbert marginal spectrum(HMS)analysis scheme is proposed to select the candidate IMFs for trend extraction,which is based on the energy distribution of HMSs,the final filtering result is obtained.Then using the evaluation index of comparing the two kinds of filtering algorithm of filtering results,it is concluded that the optimal algorithm of each type of data.Finally,the high-precision wire results in the engineering example are taken as the true value,using two kinds of filter method for rotor data filtering processing of different order number,to determine the azimuth gain optimal filter order and recalculate the azimuth,the filtering results,through the filter before and after the azimuth filtering quality compared with the true value judgment,from the aspects of external precision to evaluate the two filtering algorithm.