| Modern satellite navigation technologies,such as China’s Beidou navigation system and the global positioning system of the United States,have been able to meet people’s various needs for global positioning and navigation.However,in extraordinary circumstances such as military conflicts,artificial satellite navigation signals are easily interfered or induced,resulting in the loss of position information on the earth by aircrafts,ships and so on,which makes it impossible for them to reach their predetermined destinations,or even reach very unfavorable geographical locations due to malicious tampering with their position information.In this case,autonomous navigation technology is needed as an emergency or alternative to satellite navigation technology to meet the needs of global positioning and navigation under the condition of satellite denial.Based on the analysis of the existing human autonomous global positioning technology and the biological autonomous navigation ability,this paper proposes a fully autonomous global positioning method based on the polarized light field of the earth and other information,which has the characteristics of full autonomy and no error accumulation.In addition,this study has certain scientific value for biologists to explore the long-distance navigation mechanism of organisms and the protection of wild migratory animals.First,the characteristics of the polarized light field of the earth based on the Rayleigh scattering model are analyzed in detail,the coplanarity of the polarized light field of the earth is revealed,which further improves the description of the polarized light field of the earth based on the Rayleigh scattering model.Secondly,an autonomous global positioning method based on the polarized light field of the earth and other autonomous information is proposed.The research results show that the mathematical essence of the method is to use the navigation vectors provided by the polarized light field of the earth and other geophysical fields to fuse into an intermediate navigation vector,that is,the autonomous earth field navigation vector,and finally solve the global position information.In addition,the global error model of the autonomous global positioning method is established,which gives the law of error transmission.The experimental device was developed,and the feasibility of the method was verified by outdoor experiments.Thirdly,in order to develop a global positioning prototype,the design of the polarization sensor with single observation direction was optimized.A calibration method based on the center symmetry of the integrating sphere is proposed.After calibration,the indoor accuracy of the sensor reaches ±0.009°.Under the condition of clear sky,the calibrated outdoor accuracy reaches ±0.05°.At the same time,the influence of indoor and outdoor calibration parameters on the accuracy of the polarization sensor is compared and analyzed.The results show that most parameters of outdoor navigation can be calibrated indoors directly,and a few parameters still need to be calibrated outdoors.Fourthly,based on the coplanarity of the polarized light field of the earth,an orthogonal algorithm for the sky polarization vector is proposed.At the same time,the coplanarity is used to transform 3-D problems into 2-D problems,which greatly reduces the complexity and timeconsuming of simulation.The simulation results show that the proposed algorithm is better than the two traditional least squares algorithms and has better robustness.In addition,the detection device of the polarized light field of the earth is improved and calibrated.The experimental results verify the effectiveness and robustness of the proposed algorithm.Finally,according to the global error model and the simulation results of the sky polarization vector orthogonal algorithm,a global positioning prototype is developed.The experimental results show that the positioning accuracy of the prototype is 45 km/1σ. |
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