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Advanced RAIM

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GPS with Receiver Autonomous Integrity Monitoring (RAIM) has been used for aircraft navigation since the mid-nineties.  Today, RAIM guarantees horizontal error bounds of one nautical mile worldwide with high availability.  With the deployment of new GNSS constellations and new signals, there is a strong interest to expand the role of RAIM in aircraft navigation.

Advanced RAIM Concept Diagram

 Advanced Receiver Autonomous Integrity Monitoring (ARAIM) is a concept that extends RAIM to other constellations beyond GPS.  ARAIM will enable the integration in the position solution of the newer GNSS core constellations that may have different properties (in particular with higher failure rates than GPS).  This inclusion will provide better levels of performance of horizontal guidance than RAIM with GPS alone.  In addition, when sufficient satellites have dual frequency (L1-L5) signals, ARAIM could enable aviation safety of life operations, including approaches with vertical guidance.

ARAIM Solution Separation Algorithm Diagram

Stanford’s research in this area started in the 2000’s, and has been instrumental in the development of both the airborne algorithm and the ground monitors for ARAIM.  The FAA currently supports Stanford’s on-going research in ARAIM.

View the RAIM/ARAIM Wikipedia article.

View PDF Presentation: Introduction to ARAIM by Juan Blanch, Stanford University,
July 26, 2016.