Precise Orbit and Clock Estimation of Navigational Satellite Using Extended Kalman Filter Applicable to IRNSS NavIC Receiver Data

Abstract

The aim of this paper is to precisely estimate the satellite orbit and clock errors using Indian NavIC receiver’s data. The process of precise orbit estimation includes trajectory generation using initial state parameters system by numerical integration, measurement modeling and finally estimation of the satellite position and clock error. Extended Kalman filter (EKF) technique used to estimate the satellite position, velocity and clock error using pseudo-range measurements from a network of four ground station positions is explained in this paper. The state parameters and the clock bias are estimated with actual and well-disturbed initial conditions. It is observed from the results obtained that estimated satellite position and clock bias errors are about 11 cm and 0.01 ns, respectively, even with well-disturbed initial state parameters. Having precise orbit positions of all IRNSS satellites, the end-user position can be determined precisely.