Receiver autonomous integrity monitoring (RAIM) - Techniques, performance and potential

The goal of receiver autonomous integrity monitoring (RAIM) for the Global Positioning System (GPS) is to provide a sufficient level of navigation integrity for all phases of flight based on the signals transmitted by the GPS satellites only. Integrity requirements for airborne use of GPS are reviewed. This is followed by the description of a baseline fault detection algorithm which is shown to be capable of satisfying tentative integrity requirements. The related issue of testing the fault detection algorithm is also briefly addressed. Preliminary performance results for the baseline fault detection algorithm are presented, along with the potential of RAIM techniques for achieving GPS integrity.