Study on the calibration method of USBL system based on ray tracing

Positioning error analysis and install error calibration method are important technical issues for the Ultra Short Baseline (USBL) positioning system to be solved to improve the positioning precision. In this paper, the influences of each kind of error source are firstly analyzed in theory formula and simulation. It is found that installation error is the more prominent one, which is needed to be calibrated before its actual application. However, the calibration method based on the average sound speed will transfer the error introduced by acoustic ray bending into the installation error directly and it also will cause a great deal of loss for positioning precision. So an installation error calibration method of USBL system based on ray tracing is proposed here to improve this problem. Simulation and field experiment data processing prove that this new method can reduce the error caused by sound speed profile.