Terrain Elevation Data Integrity Monitor and Referenced Navigation

Synthetic vision systems provide a synthesized view of the outside world to pilots on displaysintheflightdeck.Terraindatabasesonboardaircraftareusedasthesourceofterrain elevation information on synthetic vision system displays. Because the primary function of thesedisplaysistoimproveflightsafety,itisimperativethattheterraindatausedtogenerate the imagery conform to a high level of integrity. Otherwise, instead of preventing accidents, the terrain database would be cause of more. Hence, it is necessary to include an integrity monitor function that ensures the terrain data are consistent with the real world. In this paper, we revisit previously proposed concepts and present the development of a 3D spatial data integrity monitor. The framework is also extended to a terrain referenced navigation scheme such that both operations can be performed simultaneously. Presented furthermore is a Kalman filter design and its associated tradeoffs for improving the performance of the integrity monitor and navigation functions. The performance of the integrity monitor and position estimator for navigation is evaluated using flight test data collected in the vicinity of Braxton County airport in West Virginia.