Australian ATC authority studies GPS RAIM outages
Occasionally, GPS satellites are spread across the sky in configurations that prevent a receiver from calculating a good position fix.
Occasionally, GPS satellites are spread across the sky in configurations that prevent a receiver from calculating a good position fix. When that happens, the unit’s receiver autonomous integrity monitor (RAIM) will generate an alert to the pilot to use an alternative navigation source.
These events, called RAIM outages, or “holes,” can last from a few seconds to many minutes, because the satellites are always moving, essentially independently, thereby creating a constantly changing configuration as they cross from one horizon to the other. Think of RAIM holes as science fiction-like blobs, continually altering their shape and size, and frequently disappearing, as they move around the globe.
