GNSS Satellite Autonomous Integrity Monitoring (SAIM) using inter-satellite measurements

The performance of the proposed SAIM algorithm depends on the a priori knowledge of orbit errors, as well as on the inter-satellite observation geometry. By comparing all four global navigation systems (GPS/GLONASS/Galileo/Compass), it is noted that GPS provides rather good geometry because of abundant satellites in the constellation. The Compass system which incorporates additional five GEO satellites also provides sound performance.