Abstract

A study of the vertical Total Electron Content (vTEC) values as measured by the Nigerian GNSS Reference Network’s (NIGNET’s) GPS receiver in Calabar with geographic coordinates: 4.95°N, 8.32°E and geomagnetic coordinates: 6.46°N, 81.59°E has been carried out for some selected days in the year 2013. The results obtained are compared with the corresponding predictions of the three topside options for the TEC predictions (NeQuick, IRI01-cor, and the IRI 2001) of the International Reference Ionosphere (IRI) model (version 2012) over Calabar region. Despite some gaps in the measured vTEC values by the GPS receiver in Calabar, the results of this research shows high hourly and diurnal correlation of about 0.9 with the IRI-vTEC predictions for the days examined; thus supporting the viability of the receiver as a vTEC measuring device. The NeQuick option gives the best topside representation for the region.

Key words: Nigerian GNSS Reference Network’s – Global Positioning System (NIGNET’s-GPS) Receiver, vertical Total Electron Content (vTEC), International Reference Ionosphere (IRI)-Model.