Research On The Underwater Polarization Patterns With Wavy Surface For Bionic Navigation Systems

Sunlight is the most common kind of natural light.When it passes through the earth’s atmosphere,it will be scattered by atmospheric molecules,aerosol particles,and clouds,so that the scattered light in the entire sky has certain polarization characteristics.When these sky lights are transmitted underwater,they will also be affected by water surface refraction,underwater scattering and other factors,and their polarization characteristics will also change accordingly.It has been discovered that sand ants,grass shrimps and other organisms can use these polarized light to distinguish the position.Inspired by this,the bionic polarization navigation technology that uses polarized light for navigation and positioning has gradually become a research hotspot at home and abroad.In order to explore the distribution mode of underwater polarized light and provide a theoretical basis for the application of underwater polarized navigation,this article mainly conducts the following research:Firstly,using Stokes vector and Mueller matrix,a theoretical model of polarization transmission including atmospheric scattering,water surface refraction and underwater scattering is established.Among them,the atmospheric scattering process is established according to the Rayleigh scattering theory.For the water surface refraction process,the polarization transmission model of the calm water surface and the wave water surface is jointly constructed according to the law of refraction,the Fresnel formula and the Cox-Munk wave model.For the underwater scattering process,The single scattering caused by water molecules is mainly considered.Then use the established theoretical model to simulate and analyze the polarization distribution mode under water,and simulate and analyze the polarization distribution mode under clear atmosphere,calm water surface and waved water surface.The simulation results show that the polarization distribution patterns of the atmosphere and underwater are highly dependent on the position of the sun,indicating that the polarization characteristics contain azimuth information that can be used for navigation.In addition,different water surface wave conditions and underwater scattering process will also change the polarization characteristics of light.This model can be used to predict the underwater polarization distribution mode under various conditions.Finally,a polarization camera was used to build an experimental device to obtain the actual underwater polarization distribution pattern map,which was compared and analyzed with the simulation results under the same conditions.The polarization distribution rules of the two were in good agreement,which verified the theoretical model of polarization transmission established in this paper.The correctness.The research results show that the underwater polarization distribution mode is mainly related to the position of the sun,including the azimuth information that can be used for navigation,but it is also affected by factors such as water surface waves and water molecule scattering in the water.The polarization transmission model established in this paper can be used Under the condition of considering the main influencing factors,the wave underwater polarization distribution mode is accurately predicted.