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DISCUSSION ON ORBIT FITTING AND ORBIT FORECASTING OF LOW EARTH ORBIT SATELLITES

The orbit fitting and forecasting of CHAMP satellite as an LEO example is discussed.The influence on fitting accuracy in the selection of different fitting time length and different polynomial order by use of Chebyshev polynomial is analyzed,and the feasibility of orbit forecasting in a short time is discussed as well.The fitting results with Chebyshev polynomial,Lagrange polynomial and normal polynomial are compared with each other,it indicates that Chebyshev polynomial is superior to both the others.In addition,the accuracy of forecasting orbit by using Chebyshev polynomial based on the m-level orbit of single point orbiting,and numerical stability of the method is verified.it is proved that the Chebyshev polynomial can be used for real-time forecasting LEO orbit in a short time.