OBS Location and Orientation Correction Using Polarization Azimuth of Near Source Water Breaks
The OBS(ocean bottom seismometer)orientation is generally randomly directed when released to the ocean bottom,and needs to be redirected by the polarization azimuth.The OBS location is also need to be relocated.In this paper,we discuss both linear and non—linear methods using polarization azimuth of water break for inverting the OBS location and orientation simultaneously.We present an approximate formula for linear inversion and ana-lyzed error of the formula.We conduct a series of numerical experiments to test the accuracy and robustness of the two methods.Five OBS deployed in South China Sea are processed u-sing both methods.The result of numerical experiments shows that linear method is not con-vergence under some circumstances,while non-linear method has better robustness and high-er precession.We use differential evolution(DE)algorithms for non—linear method,compa-ring the cases of optimizing azimuth residuals and optimizing the difference of azimuth residu-als(double difference),the result indicates that the solutions are almost identical while the double difference scheme has a better convergence status,the DD scheme convergence at a-bout 600 iterations,where the former one convergence at about 1 000 iterations.
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