Autonomous Orbit Determination By Stellar Refraction For Spacecraft

With the developping of deepspace exploration and manned spacecraft technology, the study of the autonomous navigation for spacecraft becomes a hotspot in and abroad. This paper describes an analysis of an autonomous navigator using refraction measurements of starlight passing through the upper atmosphere.The main work in the paper is as follows:1 Spacecraft modeling study: As for the Earth-oriented three-axis stabilized satellite, a precise orbit dynamics model is established in the geocentric equatorial inertial coordinate, considering the influence of the perturbation due to the Earth shape, the Sun-Moon gravitation and the sunlight pressure.Based on the precise orbit dynamics model,the state function of spacecraft autonomous navigation systerm is established.2 Spacecraft autonomous navigation technology based on the stellar refraction is studied. Using the observation information measured by CCD star sensors and the star catalog saved, the stellar refraction angle is determined. Based on the observation function, the position and velocity of the spacecraft are determinated by the EKF and UKF. And compare.with the different of the observation functions.3, The factors of determining orbit precision are studied.The limited condition of selecting the star is discussed. Further more, the effects of the atmospheric refraction model, the filtering algorithm of navigation, the star sensor precision, sample period, and sighting star numbers on determining orbit precision are studied.And simulate on computer.