Research Of Autonomous Navigation Algorithm Based On Measured Angle Information For Near-earth Satellite

Autonomous navigation can achieve the navigation tasks autonomously by only relying on sensitive equipment onboard combined with corresponding algorithms, instead of relying on the ground support. The navigation technology of this kind can not only reduce the cost of navigation, but also greatly weakened non-autonomous or semi-autonomous navigation technology’s dependence on ground stations. With the development of space exploration, advantages of autonomous navigation technology become more obvious, and autonomy will become an inevitable trend in the future development of navigation technology.In this paper, the autonomous navigation based on measured angle information for near-earth satellite is the research object, and research of the indirect sensing horizon navigation method based on atmospheric refraction of starlight is studied intensively. The development situations of autonomous navigation based on polarized light and autonomous navigation based on measured speed information are reviewed, both of which are currently relatively new method for autonomous navigation, especially the latter, systematic, in-depth theoretical research and technology application is still blank.The main content of this paper is summarized as follows:(1) The detailed derivation and expressions of transfer matrix and measurement matrix, which are of great importance to the final simulation, are given. The system scheme of autonomous navigation and filtering method adopted by this paper are designed according to the actual situation of the simulation experiment.(2)The atmospheric density is modeled more accurately using the state equation of ideal gas, and the density scale height is modeled in continuous height by using the atmospheric data at the same time, thus a new model of stellar atmospheric refraction is established, then the improved measurement model is derived. The results of this improved measurement model are verified through computer simulations.(3)The impacts of installed location of star sensor, atmospheric density error, precision of star sensor and numbers of refraction stars on navigation accuracy of indirect sensing horizon autonomous navigation are studied through simulations. The performance of filtering method is analyzed through observing the impacts of measurement model’s coefficients on navigation accuracy. Finally, the filtering method is improved. Detailed derivation of the filtering method’s five basic equations and the filtering flow chart are given. The results of this improved filtering method are verified through computer simulations.