Extrapolation and Fitting Algorithms for GLONASS Satellite Orbit

The paper decoded the positioning data, received with GPS & GLONASS receiver of 24 channels (GG24 receiver), to get the orbit parameters of GLONASS satellites at first, and then took these data as initial value for the 4-order Runge-Kutta to orbit extrapolation and compared the extrapolation position with the position in broadcast ephemeris of GLONASS. The experiment indicates that the average positioning error of extrapolation position is less then 1.5 m. Meanwhile, it took Lagrange Interpolation and Chebyshev polynomials fitting these two methods to fitting the satellites´ orbit and compared with the extrapolation, the result indicates that the Chebyshev polynomials fitting could get a small error.