Autonomous Prediction of GPS and GLONASS Satellite Orbits

Abstract

A method to predict satellite orbits in a stand-alone consumer-grade GNSS navigation device is presented. The motivation for this work was to reduce the startup time of a navigation device without the use of network assistance. The presented orbit prediction method works for both GPS and GLONASS, achieving median accuracies of 58 and 23 m in satellite position, respectively, for prediction up to four days ahead. A simple method for prediction of the satellite's clock offsets is also discussed. A basic analysis indicates that the method gives a line of sight range error of 15 m, for both GPS and GLONASS, with most of the error due to the clock offset prediction. Copyright © 2012 Institute of Navigation.