Analyzing Satellite Orbit Error for ARAIM Offline Monitoring

In this paper, we propose a new approach to generate the Integrity Support Message (ISM) for Advanced Receiver Autonomous Integrity Monitoring (ARAIM). In our approach, we analyze the satellite ephemeris parameters that directly contribute to the satellite position error and thus, result in the ranging error for an ARAIM user. First, we develop an ephemeris parameter error model for the broadcast GPS legacy navigation message (LNAV) under nominal conditions. Then, we describe the procedure to produce Signal-In-Space Ranging Error (SISRE) using the ephemeris parameter error model. The nominal SISRE bias and standard deviation are generated for the ISM to capture GPS constellation performance.