Demodulation Of Tidal Harmonics In Gravity Solid Tide Signals Based On Spectral Correlation Analysis

Under the influence of the tide of the sun and the moon,a series of periodic deformations occur on the earth's surface.Gravity tide is a kind of special solid tide,which is caused by the vertical tidal force.In the form of function,we describe the earth's deformation caused by the gravitational tide.Earth's rotation and revolution and the revolution of the moon around the earth can greatly influence the change of gravity tide as everyone knows,the movement of celestial bodies are generally with regularity,whether running track or cycle time,the mechanism of gravity tide generated,then research on knowledge theory and we can.Determine the tidal gravity signal is a periodic non-stationary signal,which is consistent with the characteristics of cyclostationary signal.Therefore,in this paper,the spectral correlation analysis method is used to demodulate the harmonic wave of gravity tide signal and extract the effective information,so as to achieve the purpose of our study.Due to the combined effect of many bodies,leading to the tidal gravity signals must be a signal contains a variety of complex signals,the complex relationship between the inevitable modulation harmonic components,such as additive and multiplicative relationship modulation modulation.Direct application of spectrum correlation demodulation based on the effect of poor,difficult to effectively demodulate the clear modulation relationship,each harmonic component between the end,in view of this situation,the first step is to use another algorithm-ICA(independent component analysis)pretreatment decomposition method,the decomposition of gravity tide signals,and to extract three a harmonic component,namely long period wave,half wave systems and on wave components,of course,there are other components,but because of its low energy and very limited impact on the experiment,can be ignored,we mainly take the three road of harmonic research.When the first step,the second step is to separate each component of the spectrum correlation analysis,so as to obtain the frequency components of each component,the third step is the frequency of gravity tide tidal harmonic signal demodulation of the three frequency components and the values are compared,and then through the analysis and research,the final results is obtained.Through the spectrum correlation analysis to relationship between modulation demodulation system,long period wave and wave on wave semidiurnal tidal harmonic component in complete demodulation.To this end,through a series of processing and analysis,we can get the corresponding research information,which is helpful to the next step of the earthquake precursor information of scientific research.