Study on Model of Starlight Atmosphere Refraction from 25 km to 60 km in Autonomous Navigation for Satellite

The method of starlight atmosphere refraction is a new kind of navigation method developed based on autonomous navigation for satellite, the main direct factors of affecting it's precision are uncertainty of model of starlight atmosphere refraction. In the paper, the varying model of atmosphere density with height is given by researches on method of autonomous navigation for satellite, actual state and basic change rule of atmosphere in calm fluxion layer, based on the experiment data of atmosphere density. Further more, a model of starlight atmosphere refraction is set up, a experience formula is given of refraction angle varying with tangent height within range of height 25~60km, adopting spherical delaminating method, based on mechanism of light spread in onflow atmosphere, geometrical position among satellite, the earth, starlight tangent altitude and a relation formula between refraction angle and atmosphere density which is derived out by optics law. The simulation results show that the formulas proposed in the article accord with the change rules of atmosphere refraction, fit with the existing experience formulas, moreover take into account the influence of real varying of atmosphere density and with considerable practicality.