Autonomous fault detection with carrier-phase DGPS for shipboard landing navigation

This research focuses on airborne integrity algorithms for shipboard relative GPS (SRGPS) navigation. Airborne autonomous detection is required for navigation threats that are undetectable by integrity monitors at a shipboard differential reference station. These threats can be separated into two basic categories: (1) aircraft receiver failures, and (2) signal-in-space anomalies whose effects depend on the displacement between the user and the ship. For the anticipated carrier-phase SRGPS navigation architecture, tracking-loop cycle slips are well-known threats in the first category. Ionospheric gradient and satellite orbit ephemeris anomalies are relevant threats of the second type. Airborne autonomous monitoring algorithms to detect these threats are described in this paper. Monitor performance is directly evaluated relative to the integrity requirements for aircraft shipboard landing navigation applications.