Position Error Maps for GPS/GNSS

As our nation’s dependence on reliable satellite navigation systems for precise Position, Navigation and Timing (PNT) applications increases, any errors/uncertainties or degradation of service will have significant life, safety, and economic impacts. Ionospheric ‘space weather’ is one of the largest sources of error in PNT applications that use the Global Navigation Satellite System (GNSS) satellite constellations, including the US government’s Global Positioning Satellite (GPS) system. NOAA currently has no operational products or services to provide GPS users accurate information on the magnitude of the ionosphere-induced positioning errors, or to help them recognize conditions where degradation due to GPS scintillation may be a problem. Thus, specification and forecast products are needed to support the broad GPS user community. We propose to develop a software solution to process the existing publicly available GPS data at NOAA/SWPC to generate PPP error maps for single- and dual-frequency GNSS receivers. The proposed Phase I research effort will investigate the feasibility of integrating ASTRA’s various existing software tools to provide a now-casting and forecasting framework for GPS error mapping. Furthermore, the proposed Phase I research will develop and validate algorithms for providing ionospheric scintillation maps over the Continental US (CONUS) using GPS TEC data.