New results of ionospheric total electron content measurements from a low-cost global navigation satellite system receiver and comparisons with other data sources

Abstract

New results of ionospheric Total Electron Content (TEC) measurements obtained from a newly installed low-cost multi-frequency Global Navigation Satellite System (GNSS) U-BLOX receiver at Abuja-Nigeria (Geographic: 8.99 N, 7.38 E; Geomagnetic: 1.6 S) is presented. The paper motivates the use of the U-BLOX receiver for TEC studies in the African equatorial region. Data obtained for the periods of July-August and November-December 2020 are used. TEC data from the U-BLOX are compared with TEC obtained from a nearby high-cost GNSS receiver, and with COSMIC – RO (Constellation Observing System for Meteorology Ionosphere and Climate – Radio Occultation) TEC measurements. Corresponding TEC values from the AfriTEC and NeQuick ionospheric models are also presented. The results show an excellent level of agreement between the U-BLOX and high-cost GNSS receiver measurements. The COSMIC values were typically less than the U-BLOX and high-cost receiver values, and this is mainly attributed to the difference in TEC integration heights used for the two systems. The correlation coefficients between the U-BLOX values and values from the other four datasets are mostly greater than 0.9. The root-mean-square differences (RMSDs) between the U-BLOX and high-cost receiver values are about 2 TECU and less. The RMSDs between the U-BLOX values and values from each of the AfriTEC and NeQuick models are less than 5 TECU. The values are comparable and even lower than values computed in previous research that used TEC from highcost receivers. There is also consistent and significant agreement between 30-second ROT values computed from both the low-cost and high-cost receivers. These results summarily indicate that the U-BLOX is a good candidate for TEC studies in the region, just like the high-cost receivers.