Stochastic Estimation of Ephemerides of Navigation Satellites in Perturbed Orbits

Resumo

The errors of navigation satellite ephemerides are one of the key factors to determine the accuracy of satellite navigation. To improve the accuracy of ephemerides calculation, modern satellites are equipped with inter-satellite measurement equipment. However, random interference is inevitably present in the data transmission path and it is necessary to minimize its effect. To perform this task, it is proposed to use the stochastic estimation of ephemerides of navigation satellites that are moving along disturbed orbits in the form of a procedure of parametric optimization based on the minimization of the additive set of two functionals. The optimization of the first functional provides the minimum of uncertainty in the estimation of ephemerides. The optimization of the second functional provides the minimum of the norm of the vector of orbital parameters variations in the current time interval. To illustrate the effectiveness of the proposed approach, a numerical simulation of the satellite constellation’s ephemerides estimation was carried out for the corresponding trajectory perturbations. The simulation results illustrate the possibility to determine the ephemerides of navigation satellites with the accuracy within units of meters based on the approach considered that uses the noisy inter-satellite measurements.