New method for high-precision first break secondary positioning-search method

Currently, the secondary positioning results of geophones have become an important index evaluating seismic data explored in beach and shallow sea. Generally, the secondary positioning methods of geophone can be divided into sonar system positioning and first break positioning. The traditional first break positioning is positioning by circle intersecting circle, which should fully consider the positioning errors produced from circle positions in the process of algorithm and finely select the circles that participate the operation of circle intersecting circle to acquire the high positioning precision, which greatly reduced the operational efficiency, since the positioning errors can't be totally eliminated because of the shortcomings of algorithm, resulted in influence on positioning precision of secondary positioning. Around the issue how to improve the precision and data processing speed of first break secondary positioning, the paper presented the search method the idea of which is that finding the node of grid best aligning the first break on the grid of region nearby first positioning point of geophones, which are exactly the secondary positioning point of the computed receiver point. The paper carried out the theoretical test and case analysis for the positioning precision and operation efficiency of the method, which showed that the search method has good isotropic effect, and the positioning results have good consistencies with sonar positioning results; operation speed has been raised by 5 times and the positioning precision has also been greatly improved.