Comparison of TEC Calculations Based on Trimble, Javad, Leica, and Septentrio GNSS Receiver Data

Vladislav Demyanov,Victor Jose Gatica-Acevedo,Tatiana Ishina,Enrique Cabral-Cano,Mark Fedorov,Maria Sergeeva

doi:10.3390/rs12193268

Abstract

A Global Navigation Satellite System (GNSS) receiver is, to some extent, a “black box” when its data is used for ionospheric studies. Our results based on Javad, Septentrio, Trimble, and Leica GNSS receivers have proven that the accuracy of the slant Total Electron Content (TEC) calculation can differ significantly depending on the GNSS receiver type/model, because TEC measurements depend on the carrier phase tracking technique applied in a receiver. The correlation coefficient between carrier phase noise in L1 and L2 channels is considered as a possible indicator that shows if the L1-aided tracking technique or independent tracking is applied inside a receiver. An empirical model of the TEC noise component was provided to determine the TEC noise value in different types/models of GNSS receivers.

Highlights

Slant Total Electron Content (TEC) calculations are based on data from carrier phase and code delays of Global Navigation Satellite System (GNSS) satellite signals received by dual-frequency ground-based GNSS receivers
The results based on Javad, Septentrio, Trimble, and Leica GNSS data proved that the noise level of the slant TEC value can differ significantly if using different types/models of GNSS receivers for TEC reconstruction
The correlation coefficient between carrier phase noise in L1 and L2 channels indicates whether the L1-aided tracking technique or independent tracking is applied inside a receiver

Summary

Introduction

Slant Total Electron Content (TEC) calculations are based on data from carrier phase and code delays of GNSS satellite signals received by dual-frequency ground-based GNSS receivers. The most popular TEC-based indices are ROTI, DROTI, AATR, DIX, and DIXSG [1,2,3,4] The accuracy of these indices (and eventually their interpretation) depends on the quality of the primary TEC measurements. Temporal resolution of GNSS receiver output data can reach up to 100 Hz [5] Such a high temporal resolution allows us to detect small-scale weak ionospheric turbulences and provides a TEC measurement accuracy of approximately 10−3 TECU or even better [6,7]. Recent studies have proven that the TEC and TEC-based indices can differ significantly when derived from different types/models of GNSS receivers and based on different ionosphere-free linear combinations. Padma and Kai [11] defined the optimal ionosphere-free combination for dual-frequency receiver’s L1, L2C, and L5 GPS signals in terms of sensitivity and observation noise

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Conclusion