Accurate measurement and correction method and device of synchronous acquisition time errors of multiple codes

Abstract

The invention belongs to the field of geophysical exploration and provides a signal transmission delay measurement model and a method. The magnitude of synchronous errors needing to be corrected can be accurately measured by adopting the model and the method. The invention provides an accurate measurement and correction method and device of synchronous acquisition time errors of multiple codes. The device is applied to a towline acquisition system. The system mainly comprises a control and processing center, a data preprocessing module and acquisition nodes, wherein the control and processingcenter generates a main clock. The device comprises a delay measurement module (DMM) and a delay correction module (DCM)_i, wherein i is equal to 1,2,...,n and means the i acquisition node; the DMM is arranged in the data preprocessing module; and the DCM_i is arranged in the corresponding i acquisition node. The method and the device are mainly applied to geophysical exploration.

Description

technical field [0001] The invention belongs to the field of geophysical exploration, in particular to a device for accurately measuring and correcting multi-node synchronous acquisition time errors. Background technique [0002] Ideally, all acquisition nodes (hereinafter referred to as nodes) in the seismic streamer acquisition system should receive the "upload seismic data command (command to notify all nodes to upload seismic data)" at the same time, and will be converted at the same time The seismic data are uploaded to the control and processing center. In the traditional seismic streamer acquisition system, a high-stability synchronous acquisition master clock is set at the front end of the streamer, and each node performs synchronous conversion of analog signals under the control and coordination of the synchronous acquisition master clock. But in reality, when the "upload seismic data command" is transmitted from the system control and data processing center to a n...

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Problems solved by technology

At present, the synchronization accuracy indicated by the mainstream seismic instruments is at the microsecond level, but since the actual data collected and recorded is in units of samples, the processing method of the first sample point is the key to the synchronization acquisition accuracy of the system. At present, the mainstream seismic detection abroad The synchronization accuracy of the streamer can only reach one sampling period, such as System Four and ARIE; the synchronization acquisition accuracy of the detection streamer system of the French company Sercel, which accounts for a major share of the market, is only 0.25ms[1-3]. Therefore, the actual Acquisition synchronization accuracy is only at the millisecond level (see literature [1] for details. Luo Lanbing, Jia Yanfang. The influence of the processing method of the first sample point on the synchronization accuracy [J]. Geophysical Equipment, 2009, 19(4): 219-220.[2 ] Luo Lanbing, Dong Shixue. Research and Analysis of Seismic Data Acquisition System Delay [J]. Journal of Jilin University (Earth Science Edition), 2005, 35(S1): 62-65. Literature [3] Zhu Debing, Ping Lijiao, Zhu Ziqiang. Time difference analysis and practice of quasi-synchronous acquisition of shallow seismic exploration data [J]. Progress in Geophysics. 2008, 23(6): 1958-1962.)

With the continuous increase of the number of nodes in the seismic exploration streamer acquisition system, the transmission delay is getting larger and larger, but the methods in the existing relevant literature can only make the acquisition synchronization accuracy reach the microsecond level, such a large synchronization error will Subsequent processing of seismic data brings many adverse effects

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