Vertical Protection Level Optimization Method and Performance Analysis of ARAIM Based on PSA Algorithm

Abstract: Advanced Receiver Autonomous Integrity Monitoring (ARAIM) algorithm is one of the satellite navigation integrity enhancement technologies to assist civil aviation approach. The basic ARAIM algorithm distributes the integrity risk (IR) and continuity risk (CR) equally, leading to a conservative vertical protection level (VPL) and limiting the availability of ARAM. In this paper, a dynamic risk optimization allocation method PID-based search algorithm (PSA) is proposed. Using the minimum VPL as the optimization objective, iteratively search for the best risk allocation method assigned to each subset of faults while satisfying the constraints. And different optimization variables and objective functions are constructed to analyze the extent to which optimizing the allocation of both IR and CR risks versus optimizing the allocation of a single risk affects the level of protection. Experiments are conducted with static data from multi-GNSS experiment (MGEX) stations and vehicle-mounted dynamic data, and the experimental results show that under GPS and BDS dual-constellation observation, the ARAIM risk optimization allocation method based on the PSA algorithm can effectively reduce the VPL. The smallest VPL is obtained by optimizing the allocation of two risks at the same time, with an average optimization rate of up to 16.1%. And optimizing IR plays a more critical role in the overall protection level optimization, the magnitude of optimizing IR accounts for 68% of the complete optimization.