A New Integrity Risk Allocation Method for BDS GBAS

Integrity is an important index to describe the safety of civil aviation. In ground-based argument system (GBAS), to assign the integrity to the fault sub-items, the Radio Technical Commission for Aeronautics gives a universal allocation algorithm. It involves the internal allocation of protection level (PL) risk, internal allocation of the non-protection level risk and the overall allocation between the two assumptions. However, this traditional allocation method is both empirical and static. The former is reflected in the fact that the allocation is highly based on the simple but inaccurate assumption, and the latter is reflected in the deviation from the time-variant principle. In order to solve above problems, we combine the concepts of traditional PLs and fault-mode PLs. We optimize them to get the mini PL to improve availability. Then based on real data collected at Dongying Shengli Airport, we test the proposed scheme. Compared with the original approach, this method reduces the PL by 4.68%, 9.32%, 8.21% respectively. An allocation consequence is shown to support future BDS GBAS.