Solution of light vector superposition heading in zenith region of underwater sky polarization image

Underwater skylight polarization images can be utilized for heading measurement, offering advantages such as anti-interference and no accumulation error. A method for underwater polarization image heading estimation was presented based on the superposition of light vectors in the zenith region, with the aim of obtaining the heading angle in underwater environments. The polarization information from the zenith region was analyzed and extracted in conjunction with attitude information. Subsequently, the underwater refracted light polarization vector was synthesized with the atmospheric polarization light vector within the zenith region using superposition operations. Through optimization of the polarization vector, the heading angle of underwater targets was accurately determined. Experimental results demonstrated that the root mean square error (RMSE) of the heading angle in the proposed method was 0.30° in the tank experiment and 0.41° in the marine experiment. Moreover, in the oceans at depths of 0.98 m, 4.89 m, and 5.94 m, the RMSE of the solar azimuth was 1.10°, 2.03°, and 3.04°, respectively.