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<p>Regional ionospheric structures characterized by localized spatial variations in plasma density significantly impact radio signals and Global Navigation Satellite System (GNSS) applications. Using multi-instrument observations in the Asian sector, this study characterizes the regional ionospheric structures and their impacts on GNSS positioning. Steep longitudinal Total Electron Content (TEC) gradients exceeding 2 Total Electron Content Unit (TECU) per degree are identified within a narrow latitudinal range (20°–30°N). We reveal the limitations of current final Global Ionosphere Models (GIMs) products in capturing these steep TEC gradients. These GIMs fail to capture these gradients due to a low longitudinal resolution of 5°, among which the Chinese Academy of Sciences final GIM (CASG) and Jet Propulsion Laboratory final GIM (JPLG) products perform better than others (demonstrated by higher consistency with observed TEC gradients) due to the incorporation of new GNSS constellations and the adoption of a three-layer ionosphere model, respectively. Further statistical analysis of Standard Point Positioning (SPP) results using different GIMs shows that the positioning errors of SPP are larger in the present of steep TEC gradients. Since the CASG and JPLG are better in capturing these TEC gradients, the positioning errors of SPP using the CASG and JPLG are smaller than those using other GIMs. By combining Rate of TEC Index (ROTI) observations with kinematic Precise Point Positioning (PPP) solutions, we present the positioning errors induced by ionospheric irregularities during two geomagnetic storms (1 December 2023 and 10 May 2024 geomagnetic storms). Ionosonde and incoherent scatter radar measurements at Sanya (109.6°E, 18.3°N) are used to demonstrate how Penetration Electric Fields (PEFs) modulate post-sunset ionospheric irregularities and ultimately influence the performance of kinematic PPP. An under-shielding PEF enhances ionospheric irregularities, degrading PPP accuracy from &lt; 10&#xa0;cm to &gt; 1&#xa0;m. In contrast, an over-shielding PEF suppresses ionospheric irregularities, thereby prevent irregularity-induced PPP errors during the geomagnetic storms. These findings highlight the critical role of regional ionospheric structures and storm-time electrodynamics in GNSS positioning.</p>

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Study of regional ionospheric structures and their impacts on SPP and PPP with multi-instrument observations in the Asian sector

  • 期刊论文

  • 出版模式：

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  • 发表日期：

    2026年3月16日

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  • Bowei Liu,
  • Libo Liu,
  • Ang Liu,
  • Yuyan Yang,
  • Xiukuan Zhao,
  • Zishen Li,
  • Xinan Yue,
  • Jing Liu,
  • Huijun Le,
  • Yiding Chen,
  • Ruilong Zhang,
  • Wenbo Li

摘要

Regional ionospheric structures characterized by localized spatial variations in plasma density significantly impact radio signals and Global Navigation Satellite System (GNSS) applications. Using multi-instrument observations in the Asian sector, this study characterizes the regional ionospheric structures and their impacts on GNSS positioning. Steep longitudinal Total Electron Content (TEC) gradients exceeding 2 Total Electron Content Unit (TECU) per degree are identified within a narrow latitudinal range (20°–30°N). We reveal the limitations of current final Global Ionosphere Models (GIMs) products in capturing these steep TEC gradients. These GIMs fail to capture these gradients due to a low longitudinal resolution of 5°, among which the Chinese Academy of Sciences final GIM (CASG) and Jet Propulsion Laboratory final GIM (JPLG) products perform better than others (demonstrated by higher consistency with observed TEC gradients) due to the incorporation of new GNSS constellations and the adoption of a three-layer ionosphere model, respectively. Further statistical analysis of Standard Point Positioning (SPP) results using different GIMs shows that the positioning errors of SPP are larger in the present of steep TEC gradients. Since the CASG and JPLG are better in capturing these TEC gradients, the positioning errors of SPP using the CASG and JPLG are smaller than those using other GIMs. By combining Rate of TEC Index (ROTI) observations with kinematic Precise Point Positioning (PPP) solutions, we present the positioning errors induced by ionospheric irregularities during two geomagnetic storms (1 December 2023 and 10 May 2024 geomagnetic storms). Ionosonde and incoherent scatter radar measurements at Sanya (109.6°E, 18.3°N) are used to demonstrate how Penetration Electric Fields (PEFs) modulate post-sunset ionospheric irregularities and ultimately influence the performance of kinematic PPP. An under-shielding PEF enhances ionospheric irregularities, degrading PPP accuracy from < 10 cm to > 1 m. In contrast, an over-shielding PEF suppresses ionospheric irregularities, thereby prevent irregularity-induced PPP errors during the geomagnetic storms. These findings highlight the critical role of regional ionospheric structures and storm-time electrodynamics in GNSS positioning.