Satellite Autonomous Navigation Technology Research Based On Skylight Polarization Characteristic

With the maturing of existing navigation method and navigation technologies application becoming more and more wildly,higher requirements are put forward on new navigation information sources.Therefore,polarized navigation has emerged as a new type of bionic navigation.Modern autonomous navigation technologies include inertial navigation,celestial navigation,satellite navigation,radio navigation and various integrated navigation.However,whether it is radio navigation,inertial navigation,or integrated navigation,they are inseparable from the existing navigation methods,and the measurement methods have not changed much in nature.Moreover,these navigation methods have their own shortcomings that can not be avoided.Using polarized light for navigation is a relatively new navigation technology.It has the advantage of no accumulating errors over time,small size,low power consumption,and apt to be miniaturized.However,it is also affected seriously by the weather in the troposphere.Therefore,the polarized navigation is put forward to be applied to the flying vehicles above the clouds in this paper,including attitude measurements and orbit determination of satellites.At this rate,the polarized navigation will no longer be affected by the weather in the troposphere,and the higer navigation accuracy can be reached.Nevertheless,applying polarized navigation to satellite autonomous navigation is still in the exploratory stage.Therefore,it is quite necessary to study satellite autonomous navigation technology based on the natural polarization characteristics,which is of great significance for both enriching current navigation means and providing new source support for various integrated navigation.For the satellite autonomous navigation technology research based on skylight polarization characteristics,the specific work is as follows:First of all,the development history of polarized navigation and its status quo are reviewed from four apects,namely atmospheric polarization pattern theory,biological polarization sensing mechanism,atmospheric polarization pattern detection and polarized navigation methods.Three methods of describing polarized light are introduced,and two atmospheric scattering processes are described in detail,Rayleigh scattering and Mie scattering.Secondly,the atmospheric polarization pattern modeling and measurement method are studied.Based on the single Rayleigh scattering model,the formation mechanism of atmospheric polarization pattern is analyzed.The relatively stable polarization pattern existing in the sky is demonstrated.The polarization pattern existing in and out the atmosphere is studied.The similarities and differences between the polarization pattern inside and outside the atmosphere are compared.The observable region of the polarization pattern outside the atmosphere is analyzed.The main factors affecting the polarization pattern are discussed.In the aspect of atmospheric polarization pattern detection,the design of polarized angle sensor and polarized camera are studied with their mearsurement principles of polarization pattern.Besides,the optimal design angle for polarized angle sensor and polarized camera are demonstrated respectively.Thirdly,the methods of error analysis and error compensation for polarization angle sensor and the navigation information methods such as solar vector are studied.In the aspects of error analysis and error compensation,the main factors leading to the measurement error of the polarization angle are analyzed,and the measurement error model of polarization angle sensor is established.Then,the measurement errors caused by various factors are analyzed and verifed repectively.The method of angle error compensation based on least squares is proposed.In the aspects of navigation information extraction,three kinds of solar vector acquisition methods based on polarization angle sensor are proposed.At the same time,it is put forward that the solar vector and the geocentric vector can be extracted simultaneously from the extra atmospheric polarization pattern photographed by the polarized camera.These methods are all validated by simulation.Fourthly,the satellite attitude determination method based on polarization/geomagnetic field measurement is researched.The attitude kinematics model and dynamics model of the satellite are established.The various environmental disturbance torques of in-orbit satellites are introduced briefly,and the measurement models of the polarization angle sensor,polarized camera and magnetometer are given.Three methods of satellite attitude determination are analyzed,namely bi-vectorial attitude determination,multi-vectorial attitude determination,and state estimation method.Two methods of satellite autonomous attitude determination are put forward,one of which is based on polarization angle sensor and magnetometer and the other is based on polarization camera and magnetometer.The simulation is carried on,the results of which show that the polarization measurement can assist the satellite in attitude determination effectively.Finally,the satellite autonomous navigation method based on skylight polarization characteristics is studied.The satellite orbit dynamics model is established,and the perturbation forces of in-orbit satellites are analyzed,and the state equation of the satellited autonomous navigation system is given.Both methods of satellite autonomous navigation are proposed,one of which is based on the polarization angle sensor and the infrared horizon sensor and the other is based on the polarization camera.Then,the corresponding observation models are established respetively.For both methods,the simulation is done with the Extended Kalman Filter algorithm united and the simulation results show that the satellite autonomous navigation based on polarization measurement is feasible.In summary,a great deal of research has been done in the field of satellite autonomus navigation technology based on polarization measurement.However,there are still many deficiencies due to the author's limited ability.Finally,the author summarizes the work of full paper and looks forward to the research issues and the work that needs to be carried out in the next step.