Satellite Integrity Monitoring for Satellite-Based Augmentation System: an Improved Covariance-Based Method

Satellite integrity monitoring is vital to satellite-based augmentation systems, and can provide the confidence of the differential corrections for each monitored satellite satisfying the stringent safety-of-life requirements. Satellite integrity information includes the user differential range error and the clock-ephemeris covariance which are used to deduce integrity probability. However, the existing direct statistic methods suffer from a low integrity bounding percentage. To address this problem, we develop an improved covariance-based method to determine satellite integrity information and evaluate its performance in the range domain and position domain. Compared with the direct statistic method, the integrity bounding percentage is improved by 24.91% and the availability by 5.63%. Compared with the covariance-based method, the convergence rate for the user differential range error is improved by 8.04%. The proposed method is useful for the satellite integrity monitoring of a satellite-based augmentation system.