Calibration for Installation Errors of Ultra-short Baseline Based on Direction Cosine

Abstract In marine surveying and mapping, Ultra-short baseline (USBL) positioning system can provide accurate location information. So the USBL is the important guarantee of other marine jobs. However, under the influence of a complex marine environment, system errors, and acoustic curves, ultra-short baselines are subject to installation errors when installed, and the positioning accuracy can be seriously disturbed. To this end, this paper uses the direction cosine method to calibrate installation errors. To further improve positioning accuracy, this new method also consider the sound line correction. This method uses an equal gradient soundtracking algorithm to correct sound bending errors, constructs the error equation based on the transformation relationship between different coordinate systems by the direction cosine method, and linearizes the transformation parameters between the coordinate systems. The above two steps complete the calibration of installation errors of the USBL. The simulation results show that the underwater target position distribution calibrated by this method has a large convergence. The deviations from the data in all directions are concentrated around the zero point and approximately conform to a Gaussian distribution. The results indicate that the algorithm greatly improves the results of ultra-short baseline positioning and significantly increases the accuracy of underwater target positioning.