An efficient GPS parameter prediction method using GPS ephemeris patterns for Self-Assisted GPS

Abstract

Ephemeris parameters in navigation message data which are updated every 2 hours has irregular patterns, But in this works, we discovered regular patterns in 24h interval some ephemeris parameters (Semi-Major Axis, Eccentricity, Mean Motion, Inclination Angle, Rate of Inclination Angle, Harmonic Perturbation Terms). In this paper, we evaluate the ephemeris parameter estimation algorithms for SA-GPS using 24h interval GPS ephemeris patterns. Using 24 hours ephemeris parameter regular patterns, we propose simple estimation methods (Polynomial method, Sine estimation method) for estimation of current ephemeris parameters.