Abstract: The non-zero mean Gaussian error and the non-Gaussian error contained in the differential corrections which are broadcast from the local area augmentation system (LAAS) local ground facility (LGF) pose a strong threat to the integrity monitoring of signal-in-space. This paper advances an algorithm in which the mean inflation and non-Gaussian inflation are combined to improve the traditional sigma inflation. By selecting the appropriate inflation coefficients, the proposed method is not only able to overbound the tails of predefined errors, but also enhance effectively the LAAS availability level. Computer simulation results indicate that compared with the sigma inflation scheme, the availability level can be as high as 99.99% in the case of a fault-free satellite. Even in the case of a critical satellite failure, the availability benefit of the algorithm could be improved 18.97% and the availability level could be raised to 95.24%.

Key words: local area augmentation system, integrity monitoring, availability, sigma inflation, error overbound