[1] The global ionospheric map (GIM) is used to observe variations in the total electron content (TEC) of the global positioning system (GPS) associated with 35 M 6.0 earthquakes that occurred in China during the 10-year period of 1 May 1998 to 30 April 2008. The statistical result indicates that the GPS TEC above the epicenter often pronouncedly decreases on day 3–5 before 17 M 6.3 earthquakes...

The impact of space weather events on satellitebased technologies (e.g. satellite navigation and precise positioning) is typically quantified on the basis of the total electron content (TEC) and temporal fluctuations associated with it. GNSS (global navigation satellite systems) TEC measurements are integrated over a long distance and thus may include contributions from different regions of the...

The ionosphere is the major contributor of errors in Global Positioning System (GPS), especially during the 11-year sunspot cycle. The incoming 11-year sunspot cycle is expected to peak in 2013. The ionosphere condition is distinctly severe during ionospheric disturbances caused by high solar activity, which raises the question of how will this affect the ionosphere in the equatorial region, es...

The satellite-to-ground communications are influenced by ionospheric plasma which varies depending on solar and geomagnetic activities as well as regions and local times. With the expansion of use of the space, continuous monitoring of the ionospheric plasma has become an important issue. In Global Positioning System (GPS), the ionospheric delay, which is proportional to ionospheric total elect...

Total electron content (TEC) data, obtained from GPS satellites can be used as a tool for extracting earthquake precursor. In this paper, a pattern matching technique is used for monitoring TEC variation during and prior to the earthquake. For the experiment two major earthquake events i.e. Bhutan earthquake on 21st September 2009 and Nepal earthquake on 25th April 2015 are considered for analy...

A new method of is being developed to estimate the ionosphere’s 3-dimensional electron density distribution based on GPS slant TEC data. The goal of this effort is to develop a generalized parametric ionospheric model that is amenable to data assimilation using powerful nonlinear least-squares batch filtering techniques and related techniques. In addition to assimilating GPS TEC data, this meth...

The estimation of Total Electron Content (TEC) in the equatorial ionosphere using GPS presents a number of challenges due to the presence of strong spatio-temporal density gradients and scintillation of the satellite signals caused by F-region irregularities. In this paper we describe a methodology for real-time calibrated TEC estimation in the presence of scintillation and a highly structured ...

With a well-selected data set, the various events of the vertical E × B drift velocity variations at magneticequator-latitudes, the resultant ionospheric features at lowand mid-latitudes, and the practical consequences of these E × B events on the equatorial radio signal propagation are demonstrated. On a global scale, the development of a equatorial anomaly is illustrated with a series of 1995...