OBS clock correction method based on background noise cross-correlation technology

Abstract

The present invention discloses an OBS clock correction method based on a background noise cross-correlation technology. An ocean bottom seismograph (OBS) is employed to record to original seismic data of N days, one noise cross-correlation function (NCF) between each two stations in each day is calculated according to the original seismic data, and the symmetry analysis method of the NCF in eachday is employed to calculate the clock difference between the stations. A reference NCF is formed by dynamic clock difference correction overlapping of the NCFs of all the days, and static clock difference is obtained according to that the reference NCF is subjected to positive and negative arrival; dynamic clock difference is obtained according to the NCF of each day and when the reference NCF issubjected to cross-correlation positive and negative arrival; and the total clock difference is the sum of the static clock difference and the dynamic clock difference. The OBS clock correction method employs the symmetry analysis method of the NCF in each day to obtain the static and dynamic clock difference between the stations so as to solve the clock difference correction problem between theOBSs when the external GPS cannot perform effective time service and in the special condition of nonlinear variation of the clock difference.

Description

technical field [0001] The invention belongs to the technical field of submarine seismic observation, and relates to an OBS clock correction method based on background noise cross-correlation technology. Background technique [0002] Seabed seismic observation technology is a direct and effective means for long-term real-time observation of mid-ocean ridge hydrothermal activities by deploying submarine seismograph (hereinafter collectively referred to as OBS) arrays on the seabed. Since electromagnetic waves cannot propagate in seawater, OBSs cannot ensure the unity of internal clocks of seismometers through external GPS real-time timing methods like land seismometers, but use the crystal oscillator inside the seismometer as the hardware device for time counting. Due to the influence of temperature, self-aging and other environmental factors on the crystal oscillator, the vibration frequency of the crystal oscillator will drift, which eventually leads to a deviation between ...

AI Technical Summary

Problems solved by technology

This method is simple and practical, but it is not suitable for the case where the clock error is not linear or the OBS is not synchronized with the GPS after recovery.

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