Research On The Skylight Polarization For The Bionic Micro-nano Navigation System

The ability to navigate in a complex environment is crucial for both animals and robots. Many animals use different navigation strategies to survive in their living environment. For example, the desert ant Cataglyphis is able to forage in hundreds of meters away while returns back to its nest precisely on a straight line. Biologists' research shows that the desert ant Cataglyphis can navigate with the help of the skylight polarization. It is because that there is relatively stable polarization distribution in the sky, at the same time, ant's visual nervous system is extremely sensitive to the orientation of skylight polarization.The physics foundation and basic optics principle of polarization are presented in this paper, and then the research on both distribution model of skylight polarization and the polarization testing system that imitates the structure of the ant's compound eyes is focalized.For skylight polarization, skylight polarization' principle and its distribution model are explored. Effects of the solar position on the polarization distribution model of the entire skylight are discussed. Based on the Rayleigh scattering theory and Astronomy knowledge, solar position, polarization degree, polarization azimuth angle and the Stokes vector information on the beam of light in the sky are given. In the VC environment, C++ language and OpenGL software kit are used to program. Two-dimensional and three-dimensional model of skylight polarization are established, solar position's movements and skylight polarization's real-time changes are dynamic simulated.Based on the desert ant' s navigation strategy, the polarization testing model imitating the structure of the ant's compound eyes is discussed, and a polarization testing mechanical device including a built-in six polarization channels is designed, in which polaroid and silicon photodiode are laid. The polarization testing system is made up of the mechanical device, photo-processing module and data acquisition module. In the experiments, three-channel polarization signals are acquired by the testing system successfully, the law that the ant's visual nervous system is sensitive to the orientation of skylight polarization is validated well by experimental curves.