摘要: Advanced RAIM (ARAIM) for vertical guidance hasattracted considerable attention both from integrityproviders and receiver manufacturers, due to its potentialto achieve worldwide coverage of vertical guidance with areduced investme... 展开 Advanced RAIM (ARAIM) for vertical guidance hasattracted considerable attention both from integrityproviders and receiver manufacturers, due to its potentialto achieve worldwide coverage of vertical guidance with areduced investment on the ground segment compared toSpace-based Augmentation Systems. Several useralgorithms have been published, mostly variants ofsolution separation and possible optimizations. Thesedescriptions have mostly focused on the definition of theVertical Protection Level (VPL), because that is what wasneeded to simulate ARAIM availability as a function ofdifferent parameters and constellation configurations.However, an ARAIM user algorithm has many moreelements that need to be defined. The purpose of thiswork is to describe an Advanced RAIM user algorithmstep-by-step including: the Integrity Support Message(ISM) processing, the fault detection and exclusion, andthe Protection Level calculation – including theHorizontal Protection Level. In this description, weattempt to clarify areas that have remained undefined.We give the contents of the ISM contents, and aclarification of the interpretation of its parameters. Theseparameters describe both the nominal error behavior andthe probability of fault of one or more satellites. Thenominal error is characterized by two sets of standarddeviation and maximum bias, the first one for integritypurposes and the second one, less conservative, foraccuracy and continuity evaluation purposes. We showhow to compute the nominal error model as a function ofthe ISM content, and how to determine which faults mustbe monitored – including which subset solutions must becomputed and compared against the all-in-view solution.In this paper, we make explicit under which conditions afault must be declared. In addition to the solutionseparation statistics, we show why it is prudent to includea chi-square test on the residuals as well. We alsodescribe the actions that follow the detection of a fault orfaults, and under which conditions fault exclusion can beperformed. Although this is not expected to befundamentally different than the current approaches inhorizontal RAIM, there are differences that arise.As mentioned above, the Vertical Protection Level hasbeen defined in several publications (each with smallvariations). In this paper we address the implementationdetails in both the VPL and the HPL. First, in case a largenumber of fault modes need to be monitored, a largenumber of subset solutions must be computed. We showhow to efficiently compute the subset solutions. Second,the PLs that provide good availability typically require aniterative halving algorithm. We describe a method tocompute a tight upper bound with very few steps. Inaddition, we provide the formulas for the EffectiveMonitor Threshold, the fault free 10~(-7) error bound, and the95% bound on the accuracy. A concrete numericalexample is given to facilitate the verification of theprovided formulas and algorithms. 收起