Study Of Sky Ultraviolet Polarization Patterns Under Cloudy Atmospheres

Mimicking the mechanism of insect polarized vision navigation,using skylight polarization patterns for navigation is currently a popular research direction in bio-navigation technology.It is found that cloudy weather can weaken skylight polarization,causing difficulties in extracting directional information using sky polarization patterns,and even leading to navigation failure.How to maximize the reliability of skylight polarization detection under cloudy atmospheric conditions has become an important topic in bionic polarization navigation research.Light waveband is an important factor affecting sky polarization patterns.Biological studies have found that insects tend to use UV waveband for sky polarization pattern detection,and UV waveband may be more suitable for sky polarization navigation under cloudy weather.For the UV-band sky polarization mode,there is a lack of atmospheric modeling and simulation that meets the actual cloudy conditions,and a lack of rational analysis of the UV polarization dominance and the influence mechanism of clouds on sky polarization.Therefore,an in-depth study of the UV-band sky polarization patterns under cloudy atmosphere is needed.The paper focuses on the following aspects of research.Firstly,the atmospheric polarization light transmission model under cloudy atmospheric conditions is established.Based on the Mie scattering Monte Carlo method,the actual atmospheric light transmission process is simulated by constructing various forms of parameters such as atmosphere,clouds,and surface albedo rate to obtain the simulated sky polarization pattern model.Based on the model,the sky polarization simulation GUI software is prepared to calculate and plot the specific sky polarization degree and polarization angle by inputting the information of time,latitude and longitude,and atmospheric parameters.Secondly,through the simulation of sky polarization patterns under different weather conditions,the polarization characteristics of UV band and other bands are compared,the relevant laws are summarized,and the physical mechanism of cloud cutting sky polarization is studied.Through the analysis of single-particle Mie scattering,the simulation of multi-particle scattering medium,the derivation of the physical reasons for the cloud medium cutting sky polarization,and finally determine the physical reasons for the role of clouds to cut polarization and the advantages of UV sky polarization.Finally,outdoor observation experiments are conducted to obtain the sky polarization pattern maps in the visible and UV bands using the visible polarization camera and the UV camera respectively,and the simulation analysis in the above paper is verified through the comparison of the actual observation data.In this paper,we propose a feasible explanation for the reduction of sky polarization by clouds through the simulation and experimental study of the UV sky polarization mode,and analyze that the UV band has higher polarization advantage in cloudy weather.The experimental results show that the UV band can still effectively detect sky polarization information under cloudy weather,and is more adaptable to complex atmospheric conditions such as cloudy weathers than the visible band.