矢量叠加初至波定位方法及精度评价

海上勘探的海底电缆或节点检波器沉放过程中，因受洋流、潮汐、缆绳等因素影响，沉放位置会发生漂移现象，故有必要对检波点进行二次定位以确定其在海底的准确位置。为此，文中提出矢量叠加初至波定位方法。通过构建每个炮检对的位置矢量，进行矢量叠加，得到检波点的准确坐标位置，并给出定位精度的量化评价指标，形成了一套从初至拾取、定位计算到定位精度评价的完整定位方法。实际数据应用结果表明，利用该方法能得到海底电缆或节点检波器准确的二次定位结果，还可对定位精度做出定量评价，具有广阔的应用前景。

First-break positioning and accuracy evaluation based on vector superposition

Influenced by current, tide, cable,etc., the final position of submarine cable or node geophone would drift from the designed position in offshore seismic survey, so that it is necessary to determine the exact position of the receiver point on the seabed through secondary positioning. A first-break positioning method, namely a vector superposition method, is proposed in this paper. The exact coordinates of the receiver point can be obtained by constructing the vector of each source-receiver pair and vector superposition. And integrating with the quantitative evaluation index of positioning accuracy, we get a positioning method involving first break picking, positioning calculation and posi-tioning accuracy evaluation. Applications to raw data have proved that the method can provide accurate secondary positioning results of submarine cable or node geophone, and quantitatively evaluate the positioning accuracy. It has a wide application in marine seismic survey.