Orbit Determination Of Spacecraft-interpolation Method And Fitting Method Of Satellite Coordinates

Orbit determination of spacecraft is an important research aspect of space systems,this paper aims to solve how to determine the trajectory of the spacecraft in a better waythrough different considerations. The main research work is as follows:1、A series of basic theory required of the orbit determination of spacecraft aresystematically expounded, including7kinds of commonly used time system,7kinds ofcommonly used coordinate system, two body motion, the transition between statequantities and orbital elements in the initial orbit determination, the disturbed motionwhich should be considered in orbit improvement, and Kalman filtering method fororbit extrapolating.2、The process of calculating the instantaneous satellite position and velocity byGPS broadcast ephemeris is studied, and realized by simulation, and the least squaresfitting method of broadcast ephemeris parameters is introduced.3、 In the studies of interpolation methods of satellite coordinates, threeinterpolation methods are introduced firstly, and then the Lagrange polynomialinterpolation method is studied emphatically from the interpolation cycle, interpolationorder, the positions of interpolation points, finally the sliding Lagrange symmetricalinterpolation method is studied, also the performances of these three methods arecompared simply.4、In the studies of the fitting methods of satellite coordinates, the Chebyshevpolynomial fitting method and Legendre polynomial fitting method are introducedfirstly, and then these two methods are studied from the polynomial order, the positionsof fitting points and the fitting scenario, and compared by the precision which is dividedinto two aspects of fitting degree and accuracy, and finally they are compared with thesliding Lagrange symmetrical interpolation method.5、The Piecewise three times Bezier curve interpolation method and the three timesB-spline curve interpolation method are used respectively to estimate the motion curvesof satellites, and then realized and analyzed by simulation experiment under thecondition of the precise ephemeris.