  NavIC is a newly established Indian regional Navigation Constellation with 3
satellites in geostationary Earth orbit (GEO) and 4 satellites in
geosynchronous orbit (GSO). Satellite positions are essential in navigation for
various positioning applications. In this paper, we propose a Bootstrap
Particle Filter (BPF) approach to determine the satellite positions in NavIC
constellation for short duration of 1 hr. The Bootstrap Particle filter-based
approach was found to be efficient with meter level prediction accuracy as
compared to other methods such as Least Squares (LS), Extended Kalman Filter
(EKF), Unscented Kalman Filter (UKF) and Ensemble Kalman Filter (EnKF). The
residual analysis revealed that the BPF approach addressed the problem of
non-linearity in the dynamics model as well as non-Gaussian nature of the state
of the NavIC satellites.
