Spectral Correlation Analysis Of Gravity Solid Tide Signals

Tidal gravity is formed by the tidal force of the earth’s surface which is generated from the sun and the moon, besides it is formed by the earth’s tidal deformation. The tidal gravity’s change is related to earth’s rotation, revolution of the moon around the earth and the earth’s rotation around the sun, these objects’running have the feature that cyclostationary so that the tidal gravity periodically and smoothly changes, that is to say the tidal gravity signal is cyclostationary signal. The main contents of this article is the tidal gravity signal’s demodulation by using the method of cyclostationary signal’s spectral correlation characteristic.On the basis of the tidal gravity signal having cyclostationary characteristic which has been analyzed in this article, demodulate and analyze the tidal gravity signal by using spectral correlation method. For additive and multiplicative components in the tidal gravity signal, firstly pre-processing the tidal gravity signal using the EMD (Empirical Mode Decomposition) method and obtaining four IMF (Intrinsic Mode Functions) components from decomposing tidal gravity signal’s additive component, And then separately analyze each IMF component in spectral correlation method, and get frequency components in these four IMF components. From each frequency component contrast to the sun and the moon’s main tidal wave’s theoretical frequency can get that:base on spectral correlation method can effectively demodulate the modulation relationship among year-wave, month-wave, halfmonth-wave, daily-wave and halfdaily-wave. The last, it concluded that using EMD method to pre-process, and then demodulate the IMF component in spectral correlation demodulation method, processing and analyzing the frequency components obtain geophysical information which is corresponding to tidal gravity orthogonal decomposition model.