Underwater positioning method based on polarization characteristics

Underwater polarization positioning is mainly to determine the heading by calculating the position of the solar meridian through the polarization distribution patterns. However, in the actual environment, the polarization state of light will be changed by atmospheric scattering, water surface refraction and underwater scattering, resulting in the reduction of the accuracy of solar meridian extraction. In this paper, a method of extracting solar meridian based on RANSAC is proposed. Firstly, the polarization images are denoised by Gaussian filter, and then the underwater polarization distribution pattern is obtained. Then the position feature points of the sun and the solar meridian are extracted by iterative threshold method. Finally, the direction of the solar meridian is fitted by RANSAC algorithm, and the carrier orientation is calculated by the angle between the body axis and the solar meridian. Simulation experiments are conducted to analyze the performance of the proposed method and the least square method under the same noise conditions. The results preliminarily confirm the effectiveness and accuracy of the proposed method in underwater environment.