A Station-Specific Ionospheric Modeling Method for the Estimation and Analysis of BeiDou-3 Differential Code Bias Parameters

Abstract

A modified generalized trigonometric series (GTS) function is presented for the joint estimation of local ionospheric activities and differential code biases (DCBs) of the third-generation BeiDou navigation satellite system (BeiDou-3). Using observational data from the iGMAS and IGS-MGEX networks, DCBs between the pilot-, data- and I-components of BeiDou-3 signals are estimated and analyzed for January 2019. The stability of the modified GTS-based satellite DCB estimates an improvement of about 29.7% compared to the original GTS-based results. In comparison with transmitted TGDB1Cp and TGDB2ap parameters, the consistency between broadcast and post-processed biases reaches 0.33 and 0.50 ns. The estimated data-pilot biases are observed to be notably smaller than BeiDou-3 transmitted inter-signal correction (ISC) parameters. In the analysis of receiver B1I-B3I, DCBs generated from the independent BeiDou-2 and BeiDou-3 constellations, the receiver-type dependent biases are emphasized, which raises the consideration of using receiver-group specific bias concept in the future estimation of BeiDou DCBs.