Bounding integrity risk for ARAIM solution separation method

Advanced Receiver Autonomous Integrity Monitoring (ARAIM) is designed to ensure the integrity risk within the predefined level. To decide whether ARAIM can achieve the requirement of integrity for safety applications, an online evaluation of integrity risk is necessary. Furthermore, the performance of ARAIM can be improved by online optimizing the allocation of integrity risk and the continuity risk among the fault hypotheses. To meet the real-time requirement, the bounding method is necessary for online evaluation of integrity risk. In this paper, the bounding model of integrity risk for ARAIM Solution Separation (SS) method is described. The model of the upper-bound in parity space is derived. On this basis, the selection of model parameters is discussed and the impact of the satellite geometry and detection threshold on the bounding performance is analyzed. The theoretical analysis and simulations demonstrate that the bounding method proposed in this paper can obtain tight bounding performance. Affected by the satellite geometry, the bounding tightness for the satellite with higher weight in positioning is less tight than that with lower weight using baseline SS method. The bounding performance for the satellite with higher weight can be improved using optimized SS method when compared with baseline SS method.