Hybrid Integrity for Precision Guidance and Landing

The goal of the Joint Precision Approach and Landing (JPALS) Shipboard Relative GPS Concept SRGPS program is to provide a GPS-based system capable of automatically landing an aircraft on a moving aircraft carrier under all sea and weather conditionsconsidered feasible for shipboard landings. The continuity and quality of the GPS satellite measurements critically drive the overall SRGPS navigation continuity and integrity. Faulty measurements, even if detected prior to transmission, impact systemperformance. Therefore, improvements are needed in the SRGPS shipboard reference station and signal processing to assure the continuity and integrity of the SRGPS correctionsUnder Phase I of this SBIR, a design was developed for a hybrid integrity solution. The integrity solution leverages the capabilities of next generation digital spatial processing and ultra-tightly-coupled (UTC) GPS/inertial integrated military UserEquipment (UE). A design was developed for a spatial environment integrity monitor that operates using digital pre-correlation and post-correlation calibration signals generated by the receiver spatial and signal processing electronics. An integratedGPS/inertial receiver autonomous integrity monitor solution (GI-RAIM) was also developed that allows detection of small error drift rates before the inertial solution can be corrupted. An integrity monitoring function embedded within the Kinematic CarrierPhase Tracking (KCPT) positioning algorithms was also developed. Under this Phase II effort, we will design, build and test an aircraft GPS/inertial digital spatial processing receiver, the HAGR-A, which will be used as a test bed under the Phase II effortfor implementation and testing of these integrity monitoring techniques. The HAGR receiver test bed will provide a platform for the testing of different antenna arrays under evaluation for use in the SRGPS system, as well as new integrity monitoringalgorithms. The modular nature of the GI-RAIM GPS/inertial integrity monitoring algorithm developed under this effort will allow it to be embedded within other manufacturers' existing architectures providing additional signal integrity for military andcommercial integrated systems. The algorithms are designed to be synergistic with existing approaches for integrity monitoring (e.g. AIME) and KCPT precise positioning. Applications exist for the JPALS and SRGPS precision approach and landing systems andfor GPS/inertial guided munitions. Commercial applications also exist for the Local Area Augmentation System (LAAS).