Accurate Multiple Ocean Bottom Seismometer Positioning in Shallow Water Using GNSS/Acoustic Technique.

Area of Science:

• Geophysics
• Oceanography
• Acoustic positioning

Background:

• Global Navigation Satellite System (GNSS) and acoustic techniques are vital for ocean bottom seismometer (OBS) positioning, particularly in oil exploration.
• Existing single transponder methods overlook environmental similarities between transponders, leading to inaccuracies.
• Sound refraction significantly degrades positioning accuracy in shallow waters with large incidence angles.

Purpose of the Study:

• To analyze the impact of sound ray bending on positioning accuracy in shallow water environments.
• To propose a novel piecewise incidence angle model for estimating sound ray bending correction.
• To enhance the positioning accuracy of multiple underwater objects, such as seismometer transponders.

Main Methods:

• Sound ray tracing method applied to analyze sound ray bending in shallow water.
• Development of a new piecewise incidence angle model to estimate sound ray bending correction.
• Sequential least squares method used to estimate model parameters, incorporating data from multiple transponders.

Main Results:

• The proposed method effectively utilizes acoustic observation data from numerous transponders.
• Accurate estimation of sound ray bending (SRB) correction is achieved.
• Significant improvement in the positioning accuracy of multiple transponders demonstrated.

Conclusions:

• The developed method offers a robust solution for enhancing underwater acoustic positioning accuracy.
• Accurate SRB correction is crucial for reliable OBS deployment and data acquisition.
• The findings have practical implications for offshore exploration and monitoring.