Fault Detection and Exclusion Using Normalized Solution Separation and Residual Monitoring Methods

: To achieve the navigational integrity required for civil aviation use of GPS, the GPS fault detection and exclusion (FDE) function is of considerable importance. In this paper, we propose a new FDE approach for tightly integrated GPS/inertial sensors that combines a normalized solution separation for fault detection and a residual monitoring scheme for fault exclusion. The computation of the detection threshold, the horizontal protection level (HPL), and the horizontal uncertainty level (HUL) is discussed, and simulation results are presented. We also develop an FDE algorithm for snapshot navigation methods based on a normalized solution separation scheme. This topic is of interest not only as a limiting case for the general filter problem, but also from a purely technical perspective. The normalized solution separation method is shown to be equivalent to other snapshot FDE algorithms.