Space Weather Disrupts Low-Latitude Network RTK: Evidence From LSTIDs During June 2025 Geomagnetic Storm

The geomagnetic storm on 1 June 2025 generated pronounced large-scale traveling ionospheric disturbances (LSTIDs) over China, captured by dense GNSS networks. It has been unclear whether network real-time kinematic (NRTK) positioning, which relies on spatial interpolation from multiple reference stations, remains effective under such extreme space weather conditions. This study provides direct observational evidence that links the passage of LSTIDs to the degradation of NRTK performance in a low-latitude region. We identified strong LSTIDs with amplitudes of ±0.4 TECU propagating equatorward at speeds of 0.3–1.3 km/s and wavelengths of 1,150–1,600 km during the storm's main phase. These ionospheric gradients disrupted the spatial correlation assumed by the NRTK algorithm, leading to interpolation residuals exceeding 10 cm. The largest residuals were mainly associated with satellites to the south of the user station, indicating that the LSTID impact may be modulated by satellite azimuth. As a result, integer ambiguity resolution frequently failed, reducing the horizontal positioning accuracy to the 5–10 cm level. These findings delineate a complete observation-based pathway from geomagnetic activity to decimeter-level positioning errors, confirming a specific vulnerability of advanced high-precision navigation infrastructure to LSTIDs during space weather events.