For low earth orbit (LEO) satellite GPS receivers, space-based augmentation system (SBAS) ephemeris/clock corrections can be\napplied to improve positioning accuracy in real time.The SBAS correction is only available within its service area, and the prediction\nof the SBAS corrections during the outage period can extend the coverage area. Two time series forecasting models, autoregressive\nmoving average (ARMA) and autoregressive (AR), are proposed to predict the corrections outside the service area. A simulated\nGPS satellite visibility condition is applied to the WAAS correction data, and the prediction accuracy degradation, along with the\ntime, is investigated. Prediction results using the SBAS rate of change information are compared, and the ARMA method yields a\nbetter accuracy than the rate method. The error reductions of the ephemeris and clock by the ARMA method over the rate method\nare 37.8% and 38.5%, respectively.The AR method shows a slightly better orbit accuracy than the rate method, but its clock accuracy\nis even worse than the rate method. If the SBAS correction is sufficiently accurate comparing with the required ephemeris accuracy\nof a real-time navigation filter, then the predicted SBAS correction may improve orbit determination accuracy.
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