Calculation of GNSS GBAS Protection Level Based on Four-Parameter Stable Distribution Model

Ground-based augmentation system (GBAS) of the Global Navigation Satellite System (GNSS) can use ranging error correction to achieve satellite integrity monitoring. For purposes of integrity monitoring, GBAS uses error overbounding method to calculate protection level (PL). The general error overbounding modeling method is to establish a zero-mean Gaussian model for pseudorange error. However, there are problems such as “thick tail”, “asymmetric” and “zero mean” in practical applications. In this paper, we use the properties of stable distribution to propose a four-parameter stable distribution modeling method. Based on the estimation of the characteristic parameter and the dispersion coefficient, the stable distribution of symmetry parameter and position parameter are estimated at the same time. Simulation analysis shows that the four-parameter stable distribution method improves the accuracy of the protection level calculation.