Receiver autonomous integrity monitoring (RAIM) capability for sole-means GPS navigation in the oceanic phase of flight

The author analyzes GPS (Global Positioning System) RAIM capability for sole-means navigation in the oceanic phase of flight, where the position protection limit requirement for the integrity function is not as stringent as for nonprecision approaches, and yet both detection and identification functions may be required if GPS is to be used as a sole-means system. For this purpose, a novel detection and identification algorithm is developed which takes advantage of the fact that, for the oceanic phase of flight, a much larger position error is acceptable than for the nonprecision approach phase of flight. The performance of this novel algorithm and an algorithm proposed previously by others is estimated via simulation and compared. On the basis of the results, recommendations are made on how RAIM may be used if GPS is to be coupled with an inertial system to provide a sole-means capability in the oceanic phase of flight