SBAS Protection Levels with Gauss-Markov K-Factors for Any Integrity Target

Abstract

According to aviation minimum operational performance standards (MOPS), protection levels for satellite-based augmentation systems (SBASs) are to be computed as the product of the estimated standard deviation of errors and a scaling, or K-factor. MOPS recognized that K-factors were originally chosen to be consistent with certain assumptions that may not hold under all conditions. Considering the limited applicability of aviation-based K-factors, it will be important to identify a more rigorous method for deriving new SBAS applications for road, rail, or maritime use. Here we describe an innovative method applicable to any integrity risk (e.g., at 10–7 for aviation or 10–5 for maritime applications) and time interval T (e.g., 150 seconds to 1 hour for aviation or 3 hours for maritime use). This new method relies on rigorous probability justification. No restrictive assumptions are needed for the time correlation pattern of the errors. The method is easy-to-implement and applicable to any type of integrity risk or time interval T.