Estimation of Differential Code Biases and Ionosphere Maps Using GNSS

A. A. Arzhannikov, V. D. Glotov, V. V. Mitrikas

Transactions of IAA RAS, issue 60, 3–11 (2022)

DOI: 10.32876/ApplAstron.60.3-11

Keywords: GNSS, GLONASS, IONEX, GIM, TEC, DCB, ionosphere, Total Electron Content, calibration of navigation equipment, Global Ionosphere Maps, local ionosphere maps, Differential Code Bias, inter-frequency delays, Klobuchar model, Total Electron Content

Abstract

The article focuses on the problem of the Total Electron Content (TEC) estimation in the ionosphere and the calibration of navigation equipment using measurements of GNSS at the operational stage. The topic is relevant because of the influence of ionospheric delays and broadcasted inter-frequency delays on the positioning accuracy. Three different methods to estimate differential code biases (DCB) for a satellite and a receiver of all existing GNSS are briefly presented, as well as methods for constructing local and global maps of the TEC in the ionosphere. The accuracy estimation of the broadcasted inter-frequency delays for all GNSS is presented according to the data from the Information and Analysis Center for Positioning, Navigation and Timing. The error of the GLONASS broadcasted inter-frequency delay is significantly higher in comparison with other GNSS (RMS deviation is more than 0.5m for GLONASS and less than 0.1 m for other GNSS). Comparing four methods of calculating GLONASS $DCB^{SC}$ showed that all four $DCB^{SC}$ sets have RMS deviation between themselves less than 0.1 m. The RMS deviation of other ionospheric maps in relation to the Information and Analysis Center for Positioning, Navigation and Timing is also presented: ~1.5 TECu for August 1, 2021 ($1 TEC unit = 10^{16} electrons/m^{2}$ which corresponds to a delay of ~16 cm for L1).

Citation