Correlation between Ionospheric TEC and the DCB Stability of GNSS Receivers from 2014 to 2016

Choi Choi,Sohn Sohn,Lee Lee

doi:10.3390/rs11222657

Abstract

The Global Navigation Satellite System (GNSS) differential code biases (DCBs) are a major obstacle in estimating the ionospheric total electron content (TEC). The DCBs of the GNSS receiver (rDCBs) are affected by various factors such as data quality, estimation method, receiver type, hardware temperature, and antenna characteristics. This study investigates the relationship between TEC and rDCB, and TEC and rDCB stability during a three-year period from 2014 to 2016. Linear correlations between pairs of variables, measured with Pearson’s coefficient (), are considered. It is shown that the correlation between TEC and rDCB is the smallest in low-latitude regions. The mid-latitude regions exhibit the maximum value of. In contrast, the correlation between TEC and rDCB root mean square (RMS, stability) was greater in low-latitude regions. A strong positive correlation (R≥0.90) on average between TEC and rDCB RMS was also revealed at two additional GNSS stations in low-latitude regions, where the correlation shows clear latitudinal dependency. We found that the correlation between TEC and rDCB stability is still very strong even after replacing a GNSS receiver.

Highlights

The Global Navigation Satellite System (GNSS) receivers, which are widely distributed on the Earth’s surface, are very useful for monitoring changes in the ionosphere
Zhao et al [27] investigated total electron content (TEC) climatology from the global ionosphere maps; they reported that the semiannual behavior of the ionospheric TEC is more significant in low-latitude regions than in high-latitude regions, which is consistent with our results
At high-latitudes, the receiver DCB (rDCB) does not seem to be significantly correlated with TEC variations

Summary

Introduction

The Global Navigation Satellite System (GNSS) receivers, which are widely distributed on the Earth’s surface, are very useful for monitoring changes in the ionosphere. The ionosphere is the largest source of error in signal propagation from GNSS satellites to single-frequency GNSS receivers. Estimating the total electron content (TEC) in the ionosphere can improve the position accuracy for the GNSS users. GNSS satellites and ground receivers have their own hardware biases, which act as large sources of error in calculating the ionospheric TEC. These hardware-associated biases still remain in the ionospheric TEC after subtracting the measurements at two different frequencies. These differences in hardware biases inherent in different GNSS code measurements are called differential code biases (DCBs). Methods for estimating the DCB have been reported in many studies [1,2,3,4,5,6,7,8,9]

Results

Discussion

Conclusion