Real-time Space Weather Tool for GPS PNT Users

Abstract:

Societal reliance on precise Position, Navigation and Timing (PNT) information has steadily increased over the past few decades, with applications including financial transactions, power grid operations, air traffic control, communication systems and autonomous vehicles. These systems are in turn dependent on reliable access to the Global Navigation Satellite System (GNSS) satellite constellations, including the US government’s Global Positioning Satellite (GPS). Errors, uncertainties and degradation of service thus have the potential to have significant life, safety, and economic impacts. While it is understood that the ionosphere impacts GNSS signal fidelity and reliability, operational products that provide users with accurate information on the magnitude of the positioning errors are currently unavailable.

In order to tackle this challenge of quantifying space weather impacts on GNSS signal degradation and derived products in real time, ASTRA has developed a prototype software solution that generates the rate of total electron content (TEC) index (ROTI) and Precise Point Position (PPP) error maps over the continental United States (CONUS). This is done by processing publicly available GPS data that is broadcast by single and dual frequency receivers using the Networked Transport of RTCM via Internet Protocol (NTRIP). Additionally, we have developed statistical and machine-learning based tools for now-casting and 1-3 day forecasting of positioning and timing errors that are indicative of ionospheric scintillations. The goal of this effort is to provide end users with a real-time assessment of the environmental impacts on the accuracy and errors of the position information generated by GPS receivers and an understanding of how these impacts evolve over time.