Impact of ARAIM Nominal Bias Bounding Techniques on Final ARAIM User Performance
Résumé
Receiver Autonomous Integrity Monitoring (RAIM) has been certified to provide lateral guidance in flight operations ranging from En-route to Non-Precision Approach (NPA). Recent developments in the RAIM algorithm science, namely Advanced RAIM (ARAIM), have suggested a future role in vertically guided operations down to LPV with a decision height of 200ft [1]. However, more stringent requirements as a result of the vertical guidance application question the external risk or trust that is placed on the constellation service provision and may require the partial reduction of this risk through the use of a ground segment, identifying and removing threats and providing data through an ISM (Integrity Support Message). This ground segment should ideally be light and low-cost so not to replicate that implemented for SBAS. In addition the ISM latency [2] should ideally be allowed as long as possible to obviate the challenging and expensive communications requirements as imposed, for example, on SBAS (6 sec Time to Alert). Furthermore, the ISM should be as simple as possible to ensure the data broadcast requirements can be met with a number of solutions from ATC, to local ground communications to GEO relay. Finally, the network should be light, in the sense of a sparse and global distribution of stations.