A Method for Real‐Time Extraction of Ionospheric Phase Scintillation Index From 1 Hz GNSS Observations Using Doppler‐Aided Geodetic Detrending

Abstract

Ionospheric scintillation causes rapid amplitude and phase fluctuations in Global Navigation Satellite System (GNSS) signals, degrading signal tracking and affecting precise positioning, time transfer, and space weather monitoring. Dedicated ionospheric scintillation monitoring receivers (ISMRs) provide standard phase scintillation indices, but their high cost and sparse distribution limit large‐scale, long‐term, and low‐latency monitoring. This study proposes a real‐time phase scintillation index extraction approach for 1 Hz geodetic GNSS observations, referred to as the Doppler‐GF method. The method combines Doppler‐aided geodetic detrending with geometry‐free (GF) and elevation‐based weighting, and the resulting index is denoted by . Doppler observations are used to reduce the dominant geometric variation in carrier‐phase measurements, while receiver clock errors are estimated from multi‐satellite phase residuals using weights jointly determined by the GF variation rate and satellite elevation angle. This processing reduces reliance on external precise orbit and satellite clock products. Using values provided by ISMRs as the reference, the method is evaluated in terms of responses during intense geomagnetic storms, single‐satellite arc consistency, annual scintillation occurrence rate, event duration, error distribution, and the complementary cumulative distribution function. The results show that captures the main characteristics of ISMR‐observed phase scintillation events and agrees well with the reference in terms of disturbance response, annual statistics, and event duration. A one‐day global multi‐station analysis further demonstrates the feasibility of large‐scale real‐time monitoring, while comparisons with 50 Hz observations indicate the potential of the method for high‐rate phase scintillation index extraction.