Abstract: A new Fault Detection and Exclusion (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 is described. The computation of the detection threshold, the horizontal protection level and the horizontal uncertainty level are also presented. This new FDE algorithm is designed to enable the tightly integrated GPS/inertial sensor to be used as a primary means of navigation sensor for civil aviation.

Abstract: Deriving inertial-aided deviations for autoland systems during GPS signal interruptions involving an inertial reference system and a GPS landing system can include converting position coordinates of an aircraft from the inertial reference system to runway, lateral, and vertical coordinates. After this conversion, the method calibrates runway distance and lateral distance based on the converted position coordinates from the inertial reference system using runway distance and lateral distance from the GPS landing system with a third-order calibration filter when the aircraft is below a first height above terrain and calibrates vertical distance based on the converted position coordinates from the inertial reference system using vertical distance from the GPS landing system with a second-order calibration filter when the aircraft is below the first height above terrain.

Abstract: The present invention is a method of deriving a ground speed of an aircraft on a descent along a flight path. A vertical speed signal is produced as a function of an altitude signal and a vertical acceleration signal. The vertical speed signal is transformed to a nominal ground speed signal based upon a glide slope defined by a glide slope beam. A correction is produced based on a glide slope deviation rate representative of deviation of the aircraft from the glide slope. The nominal ground speed signal is corrected with the correction to produce a corrected ground speed signal. The corrected ground speed signal is filtered with a horizontal acceleration signal and a runway heading signal to produce a smoothed ground speed signal.