Feasibility study of overlay data transmission on the SBAS signal

Performance of space based augmentation system (SBAS) signal is evaluated under overlay data transmission situations. The overlay data transmission is assumed to occupy the same transmission frequency and orthogonal to the SBAS signal by quadrature multiplexed modulation. The evaluation is performed for several combinations of power ratio between the SBAS signal and the overlay transmission signal. Evaluation results show that the overlay data transmission on the SBAS signal would be possible for clear sky environment.