An Area Computation Based Method for RAIM Holes Assessment

Abstract

Receiver Autonomous Integrity Monitoring (RAIM) is a method implemented within the receiver to protect users against satellite navigation system failures. Research has shown that traditional methods for the determination of RAIM holes (i.e. places where less than five satellites are visible and available) based on spatial and temporal intervals (grids) compromise accuracy dueto the constraint of computation load. Research by the authors of this paper has addressed this and developed a new algorithm to determine RAIM holes using bounded regions instead of approximation based on grid points. This paper uses the new algorithm and proposes an area based method for the computation a RAIM satellite availability statistic based on the ratio of the total area of RAIM holes and the coverage area (regional or global area). Assessment over time is based on the interpolation using a model generated from snapshot spatial statistics at a relatively long temporal interval. Test results show that the area-based method for the calculation of the RAIM satellite availability statistic is significantly more accurate with less computational load than the traditional grid points based approach.