Space weather monitoring and forecast require a permanent monitoring of the ionospheric state on global scale. The world-wide use of global navigation satellite systems such as GPS and GLONASS o7ers the unique chance for a permanent monitoring of the total ionization (total electron content—TEC) of the global ionosphere=plasmasphere up to about 20000 km height. In this study we turn our attenti...

This paper reports on a fuzzy logic correction technique for the IRI90 climatological ionospheric model that uses a sparse set of GPS total electron content (TEC) measurements to provide a significant model correction over the entire sub-solar equatorial bulge. Crisp inputs, represented by a sparse set of GPS measurements of ionospheric TEC, are ingested into the fuzzy correction model which is...

The low latitude ionosphere poses a challenge to both GPS users and Satellite-Based Augmentation System (SBAS) providers. Single and dual frequency GPS receivers used in low-latitude regions can suffer from rapid amplitude and phase fluctuations known as scintillation. Scintillation occurs when the GPS or SBAS satellite signal travels through small-scale irregularities in electron density in th...

A GSV 4004A GPS receiver has been operational near the crest of the equatorial anomaly at Udaipur, India for some time now. The receiver provides the line-of-sight total electron content (TEC), the phase and amplitude scintillation index, σφ and S4, respectively. This paper presents the first results on the nighttime TEC depletions associated with the equatorial spread F in the Indian zone. The...

Natural hazards including earthquakes, volcanic eruptions and tsunamis have been significant threats to humans throughout recorded history. Global navigation satellite systems (GNSS; including the Global Positioning System (GPS)) receivers have become primary sensors to measure signatures associated with natural hazards. These signatures typically include GPS-derived seismic deformation measure...

Signal phase measured by GPS signal processors is crucial for high-resolution range measurement. However, the measured signal phase must be corrected for the the dispersive phase advance imposed by the earth’s ionosphere. Dual-frequency measurements exploit frequency dependence to isolate and correct the ionosphere-induced phase change. The correction is proportional to total electron content (...